After reviewing what may have been my mistakes in my previous attempt, I gamely gave this cake another go. This time I was careful to follow not only the recipe instructions to the letter, but also my own modification intentions.
I did some reading on the single acting baking powder I make from scratch. Everything I’ve read cautions that you must be sure to get the batter into the oven quickly quickly because the baking powder starts to act as soon as the liquid hits it. Too much delay results in a flat product. Check.
My own modifications included making only a half recipe of the crumb topping, and reducing the baking powder to 1 teaspoon. Check, check.
And the result was…still a flop. After 35 minutes I pulled it out of the oven and let it cool. It looked beautiful, as you can see. When I tried to cut it, I discovered that the preserves I used settled to the bottom of the pan, making it difficult to get the pieces out whole. Because the thing was cooked in a 9” round cake pan, it was impossible to flip the cake out without destroying the topping (later it occurred to me that I might have been able to do the two-dinner-plates flip flop thing, although the topping still would have suffered somewhat).
This time I called in a consultant to help me assess the damage and identify a mitigation plan. Alex looked at the heap of crumbs on the cutting board and suggested using a springform pan and lining it with parchment paper. We have a small problem, because I don’t think I have a 9” springform pan (just a 10”), but we’ll cross that bridge when we come to it.
My thought is that the preserves are too solid and that’s why they’re sinking. Next go around I’ll melt them, possibly with a little lemon juice, on the stove, then drizzle them into the batter. We also agreed that the batter itself could use a shot of vanilla.
By the time I’m done with it, the only remnants of the original recipe will be the flour and the preserves.