Substitute peaches for grapes?

Peach Over Supply update. I started with pickled spiced peaches from Chez Panisse Fruit. Very nice with duck, a few still in the fridge. Then took the wise words of 702551 to heart and went for compote. I chose a recipe with the magic three little words, “No peeling necessary “. The peaches were so ripe the peels sort of leapt off, so I peeled. I tested the recipe, which called for lemon juice and sugar, and one that was merely peaches and water - preferred the simpler one, so that’s what I will use for the compote stash for the freezer. Decided on the peach cake Dr. Babs suggested. It is in the oven even as I type. Much as I love cornmeal in any incarnation, my husband cannot eat corn, so I would end up eating the whole thing myself. Not a good plan. In addition, already in the freezer I have a plenitude of quart ziplocks filled with just enough wedges for a small crisp, as AJ suggested, or a Big Smoothie. Canning terrifies me, so that’s a No Go and jam just doesn’t get eaten here. Thanks all of you for the support, ideas and encouragement. Much appreciated.

Now that you have coughed up the critical fact that you are dealing with a surplus, you should consider a different approach.

Make dishes that use a large volume of peaches. Examples might include peach pies and tarts, sorbets, compotes, cobblers.

This polenta cake calls for 10 ounces of fruit, nominally two peaches. That’s not going to make a significant dent in your oversupply situation unless you bake 20-30 cakes.

I tend to make stone fruit compotes when I have an excess. It freezes well. While the main intended purpose is to put on oatmeal, I’ve also used these compotes in meat glazes, particularly pork loin roasts.

Best of luck.

Thanks everyone. My peach tree has me in a severe over supply situation, so I think I will try both Martha’s cake and the almond flour peach recipe suggested by Dr. Babs. I very much appreciate all the help.

Or, if you really want a cake made with cornmeal, you might consider trying this recipe for a peach and cornmeal cake. Given the source, I am sure it has been well tested. I certainly would give it a go.

Let us know, please, what you end up doing. ;o)

As others have mentioned I'd have some concerns about how much liquid the peaches generate.

That said, there are many varieties of peaches; some are juicier than others. And of course peaches -- like all crops -- show variation between trees, the timing of the harvest, the specific year, etc.

There are some peaches I have purchased this year that I would not hesitate to use in this cake. There are currently white peaches at my local farmers market that I would consider and I've had a couple varieties of doughnut peaches this year that would also be candidates. You'll have to make the judgment call based on what is convenient and available to you.

One slightly tedious tactic would be to cut the peaches into pieces, spread on a sheet pan and bake in the oven to evaporate some of the excess liquid.

Personally I would rather seek out peaches that are on the drier side or consider apricots which tend to be drier than peaches. It's far simpler.

Best of luck.

Another approach.
If you want to make the polenta cake recipe but with another fruit than grapes, the closest substitute is probably blueberries.
If you want to make a cake with peaches, the closest recipes sources are - as drbabs suggests - those already made and tested with peaches. Other closely related fruits include those called drupes or stone fruit. Nectarine, plum, cherry, apricot. So look to recipes with those as well.

It would be a very different consistency. Peaches throw off a lot more liquid than grapes do. I think you’d be better off using a recipe that was tested with peaches like this one
https://food52.com/recipes/282-simple-summer-peach-cake (It’s delicious). You could probably substitute polenta for the almond flour if that’s what you’re going for.