Preheat oven to 325°F (160°C). Grease and flour three 8-inch cake pans and line with parchment paper.

Whisk together flour, baking powder, and salt in a bowl. Set aside.

Cream butter and sugar in a mixer until light and fluffy. Add eggs one at a time, mixing well after each.

Gradually add dry ingredients to wet ingredients, alternating with orange juice. Mix until just combined.

Divide batter evenly among pans and bake for 30 minutes or until a toothpick comes out clean. Cool in pans, then invert onto a wire rack.

Prepare orange gelatin according to package directions. Poke holes in cooled cakes with a fork or skewer.

Slowly pour gelatin over cakes to soak evenly. Wrap in plastic wrap and refrigerate for at least 2 hours or overnight.

Whip butter until fluffy. Gradually add powdered sugar, then mix in vanilla extract and milk or cream until smooth.

Place one cake layer on a plate, spread frosting on top, then add the next layer. Repeat and frost the entire cake. Refrigerate for 30 minutes before serving.