Crumb cake made with Cognac and topped with sweet apples will have everyone asking for seconds.
Preheat oven to 325 degrees. Spray an 8-inch-square baking pan with nonstick cooking spray. Line pan with two pieces of parchment paper, creating a 1-inch overhang on all sides of the pan. Spray parchment paper with cooking spray.
Make the Apple Topping: In a medium skillet, melt butter over medium-high heat. Continue cooking until butter becomes golden brown and fragrant. Reduce heat to medium and add sugar, 1/4 cup water, and apples. Cook until apples have softened slightly and liquid is thick and syrupy, about 5 minutes. Remove from heat; stir in Cognac, working carefully as alcohol may ignite. Return to heat, and cook until alcohol evaporates, about 30 seconds. Remove from heat and cool to room temperature.
Make the Crumb Topping: In a medium bowl, whisk together flour, both sugars, cinnamon, and salt. Add melted butter and, using your fingers, mix together to form large crumbs; set aside.
Make the Cake: In a large bowl, whisk together flour, baking powder, baking soda, and salt; set aside. In the bowl of an electric mixer fitted with the paddle attachment, cream together butter and sugar until light and fluffy, 2 to 3 minutes. Add creme fraiche, egg, yolk, and Cognac; mix until well combined. Add flour mixture and mix until well combined.
Pour cake mixture into prepared baking pan. Top with apples and their liquid to cover; sprinkle evenly with crumb topping. Transfer to oven and bake until a tester inserted into the center of cake comes out clean, about 55 minutes. Remove from oven and let cool completely before serving.