I returned to an old Nigella recipe for crumble inspiration. I usually make something closer to a crisp--with oats, finely chopped nuts, brown sugar, etc. But Nigella once suggested just flour (I used 1 1/3 cup), butter (one stick, I melt it first) and a mix of demarra and white sugars (3 tablespoons each) with a teaspoon of baking powder. The pieces get less crunchy, more dreamy to bite into. I added the zest of one lemon, and no other spices.