Strawberry Rhubarb Coffee Cake

This is the kind of coffee cake that vanishes at brunch: a tender buttermilk cake hiding a ribbon of jammy strawberry-rhubarb filling, finished with a buttery crumb topping. Sweet-tart spring fruit meets soft cake meets crunchy streusel, all in one 13×9 pan.

The filling is cooked before it ever touches the batter, and that’s the key. You mash the strawberries, simmer them with the rhubarb and a little lemon juice, then thicken everything with sugar and cornstarch into a glossy, sliceable jam. Cooking it first keeps the center from going watery and raw.

Buttermilk does the cake’s heavy work, its acidity tenderizing the crumb and reacting with the baking soda for a soft, springy lift.

The layering is simple: spread half the batter, smooth the fruit over it, then drop the rest of the batter in spoonfuls so the filling peeks through. A crumb topping goes over everything before it bakes.

Kitchen Tips

• Cook and cool the fruit filling before assembling so it sets into a thick jam. A runny filling makes the cake gummy and wet.
• Slide a sheet of foil onto the rack below to catch any fruit that bubbles over the edges.
• Drop the top batter in spoonfuls rather than spreading it, so the fruit layer stays distinct and shows through.

Variations

• Use frozen rhubarb and strawberries when fresh aren’t in season, no need to thaw first.
• Swap in raspberries or blueberries for part of the strawberries.
• Add a little cinnamon or lemon zest to the crumb topping for extra warmth.