I wonder about the oven temp of 300 F. It seems too low. I even baked it longer, but it did not bake in the middle very well.
You're talking about this recipe right? http://food52.com/recipes...
From the comments on that page, you're not alone. There's a funny typo in the recipe's first instruction line where the oven temp is so my guess is that something went awry. I'd hedge with an oven preheated to 350F and monitor the cake's progress, adjusting the heat as needed. The recipe looks like one for an apple cake but instead of regular flour, there's ground almonds/almond flour. In any event, sorry to hear about the bad experience. There was likely lots of anticipation as the cake baked. Hope I'm of assistance.
How on earth did a recipe win a contest with such glaring errors?!