Crumble Coffee Cake

A quick coffee cake baked entirely in the microwave with a buttery cinnamon-brown sugar crumble on top. From mixing bowl to done in about 8 minutes of actual cooking, plus the time it takes to stir everything together.

The batter is straightforward: flour, sugar, baking powder, egg, milk, and oil sifted and blended smooth. It goes into an ungreased round glass dish (glass is key for microwave baking since it heats more evenly than plastic). The crumble topping gets sprinkled over the raw batter, then melted butter poured over everything right before it goes in.

That melted butter soaks into the crumble during cooking and creates pockets of buttery, cinnamon-sugar goodness throughout the top layer. Rotating the dish every 2 minutes ensures even cooking since microwaves have hot spots.

Pro Tips

• Use a round glass dish, not a metal pan. Metal can’t go in the microwave, and round shapes cook more evenly than square ones.
• Rotate a quarter turn every 2 minutes. This compensates for uneven microwave heating.
• The cake is done when a toothpick comes out almost clean, not completely clean. It continues setting as it rests.
• Let it cool 5 minutes before cutting. The crumble firms up and the cake finishes cooking from residual heat.

Variations

• Add chopped pecans or walnuts to the crumble topping for extra crunch.
• Mix blueberries into the batter for a fruited coffee cake version.
• Drizzle a simple powdered sugar glaze over the cooled cake for a sweeter finish.