(Czech Fruit Bubble Sponge Cake)

June: National Fruit and Veggies Month

During the coronavirus quarantine, Islander and two of her foodie friends, Karen B. and Yukiko H., tried a Zoom session and baked a cake “together apart” (even though they live within 30 minutes of each other). Since Karen is a Czech-Texan, they decided to bake bublanina, a type of sponge cake with summer fruit “bubbling” on top (hence, the name). Not having all the same ingredients on hand at the time, they made do with what they each had in their pantry. From one recipe, they got three different yet interesting results! They are noted below. Bake a bublanina during National Fruit and Veggies Month—the fun is in seeing how your results might be different from theirs, too! Dobrou chuť!


(Adapted from Tres Bohemes-Everything Czech)


  • 2-3 cups fruit (such as pitted cherries, strawberries, blueberries)
  • 2 cups flour (or 1 cup cake flour plus 1 cup all-purpose flour=pastry flour)
  • 1 teaspoon baking powder
  • 6 tablespoons butter, melted
  • 1 teaspoon vanilla
  • 1 cup powdered sugar, plus more for sprinkling on top
  • 3 eggs
  • ¾ cup plus 3 tablespoons plain kefir, sour cream or yogurt


Wash and dry fruit; if using cherries, pit them, and toss in a little bit of flour right before using in the recipe (optional). In a small bowl, combine the flour(s) with the baking powder. Set aside.

Melt and lightly cool the butter. Mix in vanilla. Combine the butter-vanilla mix into a large bowl of powdered sugar. Stir until smooth.

Add the eggs and kefir/sour cream/yogurt and stir until smooth. Gradually fold in the flour mixture with a rubber spatula until the batter is well combined and moist (there may be lumps but do not overmix or the dense cake will not bake up as light). Pour into a greased baking pan.

Sprinkle fruit on top of the pan. Bake in a preheated oven at 350 degrees F for 30-35 minutes, testing for doneness (the cake bakes up pale and not really brown on top). Remove from the oven and let cool completely. Slice and sprinkle powdered sugar on top before serving.


  • On using and choosing the fruit for this recipe: Islander used canned tart cherries in water (dull colored, soft and mushy and too sour); Karen used frozen defrosted dark sweet cherries and tossed them in a little bit of powdered sugar and flour; and Yukiko used fresh whole strawberries. Verdict: fresh fruit is best to enjoy the natural sweetness and flavor. At the time we all made this bublanina in May, fresh cherries were just starting to be in season; they were overpriced and not as sweet. But Islander bought one small bag and used a few cherries for the final photograph above.
  • On using flour: Islander and Karen used equal parts cake and all-purpose flour and Yukiko used only all-purpose flour because she did not have cake flour. Verdict: Mix cake flour and all-purpose flour to make this dense cake lighter. But it is still fine to use all all-purpose flour.
  • On using eggs: Islander and Karen used regular large eggs while Yukiko used organic eggs. Verdict: Yukiko’s cake turned out more naturally yellow in color.
  • On using kefir, sour cream or yogurt: Islander used kefir, Karen used sour cream and liquefied ¾ cup of it with three tablespoons of milk and Yukiko used yogurt. Verdict: it was easier to stir the batter with kefir while sour cream and yogurt were thicker to mix.
  • On using different pans: Islander used a 10×10 inch square pan; Karen used a 10×10 inch round pan; and Yukiko used an 8×8 inch round pan. Verdict: use larger baking pans so the fruit is not so concentrated. A 9×13 inch pan also may be used.
  • Islander’s bublanina final food photo was shot on top of a 100% wool vintage Czechoslovakian scarf.
  • Here are what Karen and Yukiko’s cakes looked like after our Zoom baking session.