I recommend making all the cakes on one day, wrapping and chilling, then make the frostings and assemble the second or third day. This cake can be made a 3 days ahead just store in refrigerator.

1. Preheat oven to 350°F. Lightly spray 2-9″ round baking pans with cooking spray and dust with flour. Remove excess flour from pans. Set aside. Adjust oven rack to middle of oven. 
2. Prepare red cake; In bowl of stand mixer with paddle attachment, add all ingredients for one cake mix. Mix on medium speed just to mix with no lumps. 
3. Measure 2 cups of cake batter and divide between the 2 prepared baking pans. Smooth tops with off set spatula. Bake in warm oven for 20-25 minutes or until toothpick inserted into center of cake come out clean. Remove from oven, wait 5 minutes then invert onto cooling rack. Wash and rinse 1 pan, grease and flour, then make second cake mix. Measure 2 cups of batter for the third red cake layer in one pan. Make another cake or cupcakes with remaining 2 cups of red batter.
4. After baking third cake and remaining batter. Wash and dry cake pans, grease and flour for white cake recipe. 
5. In bowl of stand mixer, fitted with beater attachment, mix together all ingredients for the white cake mix. Beat on medium speed until batter is mixed with lumps. Do not over mix though. Pour 2 cups of white cake batter into each prepared pan.  Bake at 350 for 20-25 minutes or until inserted toothpick comes out clean. Remove from oven and cool cake 5 minutes. Invert onto cooling rack.  Allow to cool before moving cakes.
6. Wash and dry one 9″ round cake pan, grease and flour for blue cake. Follow instructions for white cake mix only add 1-2+ teaspoons royal blue food gel to cake batter. Pour all 4 cups of blue cake batter into the one 9″ pan.  Bake cake 25-30 minutes, but check it at 25 minutes. It is done with toothpick inserted in middle of cake comes out clean. Remove from oven and cool  7 minutes in pan before inverting onto cooling rack. Invert cake.  Now have a cup of tea or coffee and rest. 
7. When cakes are cool. wrap  each layer in plastic wrap, place cakes on separate cake boards and chill until tomorrow.
8. Next day: Prepare layers: You should have 3- 1″ red layers, 2-1″ white layers and 1-2″ blue layer cakes.
9. Set aside 2 full red layer cakes and 1 white full layer cake.
10. Cut 5″ round out of the 2″ blue cake, keeping the outer blue ring intact but discarding the 5″ round.
11. Cut 5″ round out of remaining red and white layer cakes, discarding the outer rings but keeping the 5 ” rounds. As these rounds will be fit inside of the blue outer ring once cake is assembled. This is what creates the flag inside the cake.  12. Next you will skim coat each cake and set aside to firm before frosting with Swiss Meringue.

Making Buttercream For Skim-Crumb Coat-

1. In bowl of stand mixer, with paddle attachment, whip softened butter, confectioner’s sugar, cream or milk and extract. Beat on medium speed until smooth and creamy.
2. Unwrap each cake layer and with off set spatula, spread an 1/8′ thick layer of frosting on the top and sides of each cake. Before skim coating, if there is a dome on the cakes, press it down or cut for a flat surface. Each cake layer needs to be 1″ tall and have a flat surface on both sides.  Continue to skim coat all cake layers. Set cakes aside to crust while you make the Swiss Meringue. Note: If you do not want to make Swiss Meringue you can triple the recipe for the buttercream frosting recipe that you used for skim coating. It is a lot sweeter though than Swiss Meringue. But will pipe just as well and be pretty.

Make Swiss Meringue Frosting

1.  Rinse mixing bowl that comes with your stand mixer as well as the whisk attachment with white vinegar to remove any grease build up; if you skip this part your egg whites will not whip correctly. 
2. Allow 12 egg whites to come to room temperature. In medium saucepan add 2″ of water and bring water to a low simmer. Place 6 egg whites in heat proof bowl and add 2 cups of sugar. Whisk together with hand whisk to blend about 4 minutes, then place bowl of whites/sugar on top of the saucepan of simmering water. Continue to stir whites until mixture reaches 160 °F or until sugar is not grainy between fingers. Be careful mixture is very hot.
3. Transfer hot mixture into clean bowl of stand mixer. Whip the whites with whisk attachment on medium-high speed until egg whites become stiff peaks. About 10-15 minutes. The bowl will be hot to touch but will cool off as you whip the egg whites. 
4. Once whites are glossy and stiff peaked,  remove whisk attachment for paddle, add room temperature butter one tablespoon at a time whipping on medium high speed until soft and creamy meringue frosting develops. Add extracts and salt whip to blend. 
5. Fill disposable 14″ or 16″piping bag fitted with coupler with no tip Swiss meringue frosting. Measure out 2 cups of meringue frosting ( 1/2 cup frosting to frost between full layer cakes and 1/4 cup for the 5″ rounds). Fill remaining frosting in disposable piping bag fitted with large tip. You will have to make another batch of frosting for piping the dollops and shell design around bottom of cake. 

Frosting and Assembling Cakes

• Cakes are crumb coated and ready to assemble.  Place red cake on cake board or directly on cake stand-serving platter-measure 1/2 cup meringue frosting on top of cake, with off set spatula smooth frosting on top of cake to a 1/4″ thickness.
• Add white cake layer, 1/2 cup frosting smooth to 1/4″ thickness. 
• Add red layer cake, 1/2 cup frosting, smooth to 1/4″ thickness.
• Add 2″ blue cake with cut out center on top of red layer cake. Ice center of cake with meringue frosting 1/4″ thick.
• Add white 5″ round to center of blue cake, frost top of red round with 1/4 cup frosting.
• Add red 5″ round to center of blue cake on top of the white 5″ round. Press cake layers down to compact the layers and flatten cake top. If cake top is not level or flat. Trim excess cake to make it flat. Skim coat top of cake with buttercream. Place in refrigerator to chill 20 minutes before frosting with Swiss meringue. ( time for another coffee or tea break while the cakes chill, you can chill too).
• With filled piping bag with no tip, place cake on a turn table if you have one, and pipe a continual stream of frosting covering sides and top of cake.  Smooth sides with a bench or cake scrapper for smooth sides. Use off set spatula to smooth top of cake. 
• Pipe 1″ swirls of meringue on top of cake around outer edge of cake. Sprinkle with red, white and blue sprinkles. 
• Pipe shell design around perimeter bottom edge of cake using tip # 32. Sprinkle sprinkles on the shell designs if desired.  Insert red, white blue candles or a double sided foam star on center of cake. 
• * My stars are foam coasters that I taped together to stand up on center of cake. I found those at hobby lobby. there were 4 coasters in a package. 
• Keep cake chilled in refrigerator until half hour prior to serving. Serve cake at room temperature.