CHOCOLATE-RYE CRUMB CAKE

Steps:

• Crumble:
• Whisk granulated sugar, all-purpose flour, rye flour, cacao nibs, cocoa powder, and salt in a medium bowl until blended. Work in butter with your fingers to form large clumps.there should be no dry spots. Cover and chill.
• Do ahead: Crumble can be made 2 days ahead. Keep chilled.
• Cake and assembly:
• Preheat oven to 350°. Coat a 9"-diameter cake pan with nonstick spray and line with a parchment round. Whisk all-purpose flour, rye flour, cocoa powder, baking powder, baking soda, and salt in a medium bowl.
• Using an electric mixer on mediumhigh speed, beat butter, granulated sugar, and brown sugar in a medium bowl until light and fluffy, about 5 minutes. Scrape down sides of bowl and add eggs and vanilla; mix until blended, about 2 minutes. Reduce speed to low and add half of dry ingredients followed by buttermilk, mixing well after each addition. Repeat with remaining dry ingredients and yogurt (this is a stiffer batter). Scrape into prepared pan. Scatter crumble over.
• Bake, rotating once, until cake starts to pull away from sides of pan and a tester inserted into the center comes out clean, 60-70 minutes. Let cake cool in pan on a wire rack before turning out.
• Do ahead: Cake can be made 3 days ahead. Store tightly wrapped at room temperature.