This mini grapefruit cake is a moist citrus cake made with fresh grapefruit juice and zest, topped with a light grapefruit glaze, and baked in a small dish.
Grease a 5x5-inch or 4x6-inch baking dish with ½ tablespoon of butter. Place the dish on a baking sheet.
In a medium bowl, beat the butter and sugar with a hand mixer on medium speed for 1 minute until smooth.
Mix in the egg, grapefruit juice, zest, and vanilla until fully combined.
In a separate small bowl, whisk together the flour, baking powder, and salt. Gradually add to the wet mixture, mixing on low speed until just combined. Gently fold in the milk.
Pour the batter into the prepared dish and spread evenly. Bake for 40–45 minutes, or until golden and a toothpick inserted in the center comes out clean.
Let the cake cool completely before glazing.
Make the Glaze
In a small bowl, whisk together powdered sugar and grapefruit juice until smooth.
Use a toothpick or fork to poke holes all over the cooled cake.
Pour the glaze evenly over the top.
Once the glaze sets, slice and serve.
Notes
Use Softened Butter: Butter should be soft enough to indent when pressed but not melted. This helps the batter mix evenly and creates a tender crumb.
Cream Well: Beat the butter and sugar until smooth and slightly fluffy to build structure in the cake.
Measure Flour Carefully: Spoon flour into the measuring cup and level it off to avoid adding too much.
Use Fresh Grapefruit: Fresh juice and zest give the cake the best citrus flavor.
Check for Doneness: The cake is ready when the top is lightly golden and a toothpick inserted in the center comes out clean.
Adjust the Glaze: Add more juice for a thinner glaze or more powdered sugar for a thicker finish.
If doubling the recipe, double the ingredient amounts and bake in a 6x8 inch baking dish.