Lime-Grapefruit Cake with Poppy Seed Frosting

What is it like?

-light & fruity

-rich buttercream frosting

Gluten free dairy free lime grapefruit cake recipe


Makes one 9-inch round cake or one 8 x 8 inch cake. This recipe can be used to make cupcakes or whoopee pies.

1 1/2 cups (218g) flour mix
1 tsp baking soda
1 tbsp psyllium powder
1/4 tsp fine sea salt

scant 3/4 cup (157g) sunflower oil
1 cup (250g) sugar
2 eggs (107g)
1/2 cup (125g) unsweetened apple sauce
1/4 cup (51g) lime juice
1/4 cup (51g) grapefruit juice
2-3 tbsp zest (from grapefruit and limes)

1 cup (225g) butter, at room temperature (or Earth Balance for dairy free)
2 1/3 (300g) cups powdered sugar
dash of salt
2 tsp lime zest, or to taste (optional)
2 tbsp poppyseeds, or more to taste


  1. Preheat the oven to 350°F. Grease an 8x8 baking dish and line the bottom with parchment paper. If you’re doing so, make sure that your 8x8 baking dish is at least 1 1/2 inches tall. Or, for a layered cake, grease the sides of two 9-inch round cake pans with oil or butter. Cut two round parchment circles, and place them in the bottom of the pans for easy release.

  2. In a large bowl whisk together the dry ingredients.

  3. In a medium bowl whisk together the wet ingredients.

  4. Add the flour mixture to the wet mixture and whisk just until most of the lumps are gone. Pour the batter into your baking dish and bake for about 25 minutes or just until the middle springs back when pressed. Allow to cool completely before frosting.

  5. For the buttercream: While the cake bakes, prepare the buttercream. Stir together the powdered sugar and buttercream. If your powdered sugar has lumps you may want to sift it first. If you like your frosting light, you can whip it on high for a couple of minutes. Then add zest and poppy seeds. 

  6. Using a spatula, place frosting in the middle of the top of the cake and gently frost it outward with the spatula trying to avoid picking up crumbs. Keep the cake in the fridge if it’s not ready to consume.