1Prepare the lemon curd: In a microwave safe bowl, whisk together the sugar and the eggs. Stir in lemon juice and zest. Slowly whisk in the melted butter and place the bowl in the microwave. Heat the lemon mixture in 1-minute intervals until the mixture becomes thick enough to coat the back of a spoon. Refrigerate the lemon curd until it has set.
2Preheat the oven to 350 degrees. Spray an 8-inch square pan with non-stick spray and set aside. In the bowl of a stand mixer, combine butter and lemon zest. Add sugar and continue to mix until creamy. Beat in eggs one at a time, scraping down your bowl as necessary. Stir in lemon juice.
3Combine the flour, baking powder, and salt. Add flour mixture to butter mixture alternately with the yogurt. Pour batter into the prepared pan. Spread lemon curd over the batter.
4To prepare the crumb, combine the flour, sugar and butter cubes in a bowl. Break down the butter with two forks or a pastry cutter until the mixture looks like small pebbles. Sprinkle over the cake and bake for 45–50 minutes or until golden and set.
5Serve cake with powdered sugar.
Notes
Jarred lemon curd can be used in place of homemade. No source URL was visible on the printed recipe.