Sift flour, baking powder, salt, and baking soda together in a bowl.
Beat butter on high for 30 seconds.
Add sugar and vanilla extract to the butter until well combined.
Add egg whites, one at a time, mixing after each.
Add eggs, one at a time, mixing after each.
Add â…“ C flour mixture to the wet mixture followed by adding â…“ C of the buttermilk; add â…“ C flour mixture again then add â…“ C buttermilk mix on low speed, add â…“ C of flour and add the rest of â…“ C of buttermilk mix in low speed until thoroughly blended.
Divide the batter into three bowls.... add orange gel food coloring to one.... add yellow gel food coloring to the second and Leave the batter white in the third bowl.
Spray the bundt pan with Pam spray.
Begin by spooning in the white batter then the orange next then last the yellow batter on top.
Bake the cake at 350 degrees for 30-35 minutes or until an inserted toothpick comes out clean.
Allow the cake to cool in the pan for about 20 minutes then remove the cake from the Bundt pan and place on a wire rack until completely cooled.
Cream the butter and powder sugar until it looks light and creamy.
If it doesn't cream add several drops of the heavy whipping cream until it creams. Once the frosting has the right consistency then divide it into 3 bowls.
In two of the three bowls add several drops of gel food coloring. 1 st bowl add orange, 2nd bowl add yellow, 3rd bowl stays white. After each color addition stir well to mix the colors.
When the colors are right, starting with the orange frosting using a spoon drizzle the frosting on the cake. Allow the orange frosting to dry. Next again using a spoon drizzle the yellow frosting on the cake. Allow it to dry. Lastly, drizzle the white frosting on the cake and allow it to dry completely.
Substitution Consequences
Swapping buttermilk for standard milk removes the necessary acid required to react properly with the 1/4 teaspoon of baking soda listed in the ingredients. Without that specific acid-base reaction, the crumb structure loses lift and density increases significantly. Whole milk combined with a tablespoon of lemon juice replicates the required acidity and viscosity.
Thermal Management and Coloring
Gel food coloring prevents excess liquid from entering the batter compared to water-based liquid dyes. Adding these concentrated pigments requires careful folding to avoid overdeveloping the gluten network in the 2 cups of flour, which would otherwise toughen the cake. Baking at 350 degrees Fahrenheit for 30 to 35 minutes ensures the dense layers set fully before the exterior overcooks.
Freezing and Preservation
Wrapped tightly in plastic wrap, the baked and completely cooled cake sustains frozen storage for up to two months without losing moisture. Thawing must occur slowly inside the refrigerator overnight to prevent condensation from dissolving the decorative exterior frosting. Drizzle applications require complete drying between layers at room temperature to prevent the colors from bleeding together.