Preheat the oven to 350℉. Grease both pieces of a bunny cake mold and set aside.
In a small bowl, whisk together the 1 ¾ cups homemade gluten free flour blend, 1 ½ teaspoons baking powder, and ⅛ teaspoon salt.
In a large bowl and using an electric mixer on medium speed, cream the ½ cup unsalted butter,, scraping down the sides of the bowl as necessary, until the butter is lighter in color, about 45 seconds. Then add the 1 cup granulated sugar in a steady stream and mix on medium speed until the mixture is very light in color and texture, about 4 to 5 minutes.
Slowly pour in the 2 eggs, a little at a time, and beat very well for about 2 minutes.
With the mixer on low, add half of the flour mixture, then the ½ cup whole milk, and finish with the remaining flour. Scrape down the sides of the bowl in between additions.
Pour the batter into prepared cake pan and rest it for 20 minutes. Place the top on the cake pan and place on a baking sheet, then bake for 30-40 minutes, or until a tester inserted in the center comes out clean.
Remove from the oven and set on a rack to cool for 10 minutes then turn out onto rack to finish cooling completely.
Make frosting: In a large bowl, beat the ½ cup unsalted butter until light and fluffy. Add the 3-4 cups powdered sugar, the 4 drops red food coloring, and 1 tablespoon milk and continue mixing until a smooth frosting forms. Frost the top and sides of the cooled cake.
Notes
Bring ingredients to room temperature. This is always important, but especially regarding the frosting, so that it turns out smooth and fluffy. Make sure the butter is soft enough so that it easily blends with the other ingredients.
Bake according to your tin's directions. Shaped baking tins can be a bit different than regular cake pans. Some call for you to bake the cake at a lower temperature. Always follow the instructions that come with the cake tin!
Make this a regular cake. If you wish, bake this cake in a 9-inch round, parchment-lined cake pan to make a traditionally-shaped cake. Then decorate with festive Easter candies and figurines! Or, double the recipe and bake as a big, 9x13-inch sheet cake.
Rest the batter. Leave enough time before baking to allow the batter to rest in the cake tin. This ensures that the gluten-free flour mix properly hydrates, making for a smooth, plush crumb with no grittiness.