Cast Iron

Rhubarb Ginger Downside-Up OatmealĀ Cake

April 25, 2010
4 Ratings
  • Serves 8-10 slices
Author Notes

All of my favorite things in one. Fresh ginger goes great with the rhubarb and the oatmeal cake, well, is gooey and tasty. Let it cool at least 20 minutes before slicing. I top it with frothed cream but vanilla ice cream would be great too. As for the name, I have to credit Vivian my 4-year-old. She corrected me when I said upside-down cake and said it should be a "downside-up" cake. - thirschfeld —thirschfeld

Test Kitchen Notes

This is a great cake. I was a little skeptical about the whole downside-up/upside-down "thing" since this is done in a cast-iron skillet, but the cake came out beautifully! The syrupy ginger-rhubarb topping is wonderful and the cake itself is moist and delicious. I brought this to a gathering and everyone raved -- the only problem was that I forgot to bring vanilla ice cream... I won't make that mistake again. - WinnieAb —The Editors

What You'll Need
  • For the rhubarb:
  • 2 1/4 cups fresh rhubarb, 1/2 inch slices
  • 1 tablespoon fresh ginger, grated
  • 1 cup brown sugar
  • 1/4 cup unsalted butter
  • For the oatmeal cake
  • 1/2 cup thick cut rolled oats
  • 3/4 cup boiling water
  • 1/4 cup unsalted butter, 1/4 inch cubes
  • 1/2 teaspoon vanilla
  • 1 large egg
  • 1/2 cup brown sugar
  • 1/2 cup sugar
  • 1 cup unbleached all-purpose flour
  • 1 teaspoon baking powder
  • 1/4 teaspoon baking soda
  • 1/4 teaspoon salt
  1. In a mixing bowl combine the oats with the boiling water. Add the1/4 cup of butter. Set aside to cool.
  2. Preheat the oven to 350 degrees. Gently melt the butter in a 10 inch cast iron skillet. Remove it from the heat. Spread the brown sugar evenly across the bottom. In a large bowl mix the ginger and rhubarb. Spread the rhubarb evenly across the brown sugar. Set aside.
  3. In the empty rhubarb bowl combine the flour, baking powder, baking soda and salt.
  4. To the cooled oatmeal add the egg, both sugars, and vanilla. Mix to combine. Add the dry ingredients to the wet and mix until combined.
  5. Spread the cake batter evenly across the top of the rhubarb. Place into the oven and bake for 30-40 minutes.
  6. Remove from the oven when done and let cool for 5 minutes before inverting onto a cake plate. Let cool for 20 minutes before slicing.
Contest Entries

See what other Food52ers are saying.

  • ifjuly
  • Mollyh
  • abbyarnold
  • Ordinary Blogger (Rivki Locker)
    Ordinary Blogger (Rivki Locker)
  • Sagegreen

23 Reviews

Pat M. June 8, 2023
Has anyone made this in a glass cake pan? I don't have a cast iron pan handy, but I do have lots of rhubarb!
Martha S. June 1, 2020
I love this cake. I make it every year as soon as there is rhubarb. Sometimes I make it 3 times.
ifjuly March 12, 2020
Went on a major rhubarb bender this season as it's been reliably, steadily available week after week (not always the case here) and my partner adores the stuff. I've made scones, muffins, crisps/cobblers, rib sauce (!), stewed beef, stewed fish, you name it I've used rhubarb in it, phew...and this is the clear winner for the dessert category! As noted in earlier comments, it's great fresh but also remarkably delicious straight-from-the-fridge cold leftover the next day. The two of us alone gobbled it all up pretty much immediately, it's compulsively delicious. Also, I feel like the recipe "feels"/reads more complicated than it actually ends up being. Like others, I was nervous it would not unmold smoothly but it did. Wonderful. Thank you for the best rhubarb dessert I've ever made, and that is really saying something given how exhaustive my search and recipe testing over many years has been!
SandraM June 5, 2017
Made this today and really loved the flavour combo of the rhubarb with the ginger. I would have never thought to put those two together. It is definitely going to be a new favourite here. And the chew of the oatmeal is perfect with the cake. Can't wait to see what it is like the next day.
Highly recommend for anyone looking for something other than the usual rhubarb and strawberry combo dessert.
Mollyh May 19, 2015
Fabulous. A keeper.
abbyarnold June 3, 2012
I've made this cake three times, and it is gobbled up immediately each time. Last time I used a large-ish pie plate because the cast iron skillet was just too hard to handle. It does take a second person to help invert the thing, but it is all so deliciously well worth it!
Kateq April 1, 2012
Many, many thanks for this lovely recipe. I made minimal changes--I used half chopped tart apple, half rhubarb and baked it in a good, heavy cake pan instead of the cast iron. It was absolutely fabulous. Everyone raved and, as the name (especially with addition of apple) is a bit unwieldy, the youth vote was to call it "Unicorn Cake." I have already received multiple requests for more unicorn cake. BTW, my fresh ginger was living in the freezer--I grated it frozen and it was perfect. Maybe this is a little astuce known to everyone, but I was delighted to discover it.
LissaRose June 18, 2011
Never mind my previous post. I see there is also another 1/4 cup of butter called for with the rhubarb. Sorry!
LissaRose June 18, 2011
I'm a little confused about steps 1 and 2 -- step 1 says to add the 1/4 cup of butter to the oats and hot water, while step 2 says to melt the butter in the skillet. The recipe only calls for 1/4 cup of butter, though. So, are you really supposed to add it to the oats? If so, how much do you melt in the skillet? Thanks!
Ordinary B. June 9, 2011
I made this cake and it was a major hit. We enjoyed about half of it fresh, but the rest stayed really nicely in the fridge overnight. Great new addition to our repertoire. Thanks!!
GoodFoodie June 9, 2011
I cut the butter and sugar by about 25% and it was still great. I used whole wheat pastry flour and a bit of wheat germ as well. I l got a couple of comments from the family about the 'crunchy' oatmeal but I loved it as is (the oats are not cooked at all and I used thick cut oats from my farmer which are really thick). Loved it and would make this again.
Ordinary B. June 4, 2011
I came across your recipe while searching for something nice to do with rhubarb that does not involve strawberries (the season is over here in NJ). This looks wonderful. Do you think I could refrigerate this and serve it a day later? Or does it really need to be served fresh?
Sagegreen July 24, 2010
This is on my must-make list- as soon as we get some cooler weather for baking! Love the name as well. Thanks, Vivian, for that!
The D. May 20, 2010
Delicious. I finally made this last night, and love how easy it is to pop in the oven while getting on with dinner. I used a 10-inch non-stick pan, because I don't have a cast iron one, and it got a little scorched on the bottom. I guess cast iron diffuses the heat better. Anyway, it reminded me of the cake my mother used to make with garden-fresh rhubarb - except this was even better. Thanks for sharing!
guineverek May 17, 2010
I've now made this cake twice, each time to rave reviews. Instead of butter I use Earth Balance, which has a terrific buttery flavor and texture, and is made with healthy and non-hydrogenated oils. 1 TBSP has the same amount of fat as butter, but half the saturated fat, and zero cholesterol. As noted in my first comment, the cake was moist and light with a lovely crumb. I don't think you'd get that same result with oil.

I'd be concerned about oil instead of butter for the topping, because you're not going to get the same carmelization of the brown sugar and rhubarb with oil. I don't use olive oil much in baking because I personally find it has a distinctive flavor that I don't care for in sweets.
agamom May 17, 2010
Made last night for a dinner invitation at a friend's house, and it received highest marks by all. Several people in attendance had hang-ups about rhubarb, and could not believe how delicious this dessert tasted. Rhubarb is one of the few things I grow, besides flowers, and it was such a delight to go out to the garden and pick a few stalks to add to this dessert. It was fun to cook in the skillet & came out perfectly. Tried not to think about the proportion of sugar, but a small piece was heavenly and not too decadent. For the question below about the butter substitute: I often substitute 1/2 or even 2/3rds high quality olive oil for butter in recipes and rarely find that anyone notices the difference, even me. I did not try this yet for this recipe, but recommend a try.
porchapples May 16, 2010
Can you suggest a satisfactory way for making this recipe with less butter?
thirschfeld May 17, 2010
I am not sure you will reduce the fat but might reduce the over all saturated fat by switching the butter used in the cake to a non-hydrogenated shortening or you could sub a non flavored oil like safflower but it will definitely change the texture of the cake. For the topping you might try 50/50 butter and vegetable oil. These are just ideas, I haven't tested them, so if you test it let me know how it goes.
thirschfeld May 9, 2010
Thank you all for making my recipe. I am so glad you liked it.
guineverek May 9, 2010
I made this for dessert on Mothers Day after Indian buffet brunch. Its ab fab - the flavors meld together beautifully, the rhubarb keeps it from being too sweet, and the crumb of the cake is moist and light (and I used whole wheat flour instead of white). I also used quick steel cut oats instead of the rolled and they gave the cake a little nutty flavor and some extra texture. thanks for the recipe!
WinnieAb May 9, 2010
I made it for Mother's Day too! Took it to a party and everyone loved it!
The D. May 6, 2010
Can't wait to try this! Rhubarb is my favourite dessert fruit, and I love it completely unadulterated by strawberries, apples, etc. It'll be another week or two before rhubarb hits the markets here in Montreal, but this is what I'm making the moment it does!