Preheat the oven to 350 degrees F. Place the pecans on a baking sheet and bake until toasted, 10 to 12 minutes. Remove and let cool. Coarsely chop 1/4 cup of the pecans.
Put the remaining 3/4 cup pecans in a food processor along with 1/2 cup of the cake flour. (The flour will help keep the nuts from turning into pecan butter.) Pulse the pecans until they're very finely chopped. Add the rest of the flour, the confectioners' sugar, turbinado sugar, salt and baking powder. Pulse until mixed, 3 to 4 times.
With the machine running, add the melted butter and vanilla. Pulse until large clumps form. Transfer the mixture to a bowl and stir in the reserved 1/4 cup chopped pecans. Refrigerate until chilled. The topping can be made several days in advance and can also be frozen for up to 1 month.
Heat the oven to 350 degrees F. Butter eight 6-ounce ramekins or baking dishes.
Divide the lemon curd evenly among the ramekins. The curd should fill just under one-third of the ramekin. I like piping the curd into the ramekins, but using a spoon old-school works just as well.
Evenly portion the raspberries on top of the curd. Remove the crumble from the refrigerator. Break off clumps about 1/2 to 3/4 inch in diameter, keeping the clumps the same size, and divide them evenly among the ramekins.
Arrange the ramekins on a baking sheet and place in the oven. Bake until the berries start to bubble and the topping turns golden brown, 10 to 12 minutes.
Remove from the oven, let cool for 10 to 15 minutes, and serve dusted with confectioners' sugar. You can also serve the betties topped with ice cream, whipped cream or creme fraiche, or you can pour a little warm heavy cream into each betty.
Recipe courtesy of Hedy Goldsmith