Champagne cake with raspberry filling and champagne raspberry buttercream

I wanted something special for my mom's birthday cake this year. I have just finished the 4 Wilton cake decorating courses, so I knew I could make it pretty, but I wanted it to be yummy. She always makes me a delicious cake recipe for my birthday, so I wanted to do the same for her. I racked my brain for ideas and then champagne and raspberries just stuck in my head. This cake came out SO delicious. It was super easy too!
Champagne cake
1 box white cake mix (I use Duncan Hines)
Egg whites and oil (I use applesauce to replace oil)
Champagne to replace the amount of water called for on the box (Duncan Hines called for 1 cup water, but I used 1 1/4 cup champange- I used Verdi.....my favorite)

1. Grease baking pans and preheat oven according to box cake mix directions.
2. In a large mixing bowl, combine ingredients and mix according to box cake mix directions.
3. Pour mix into prepared pans and bake according to directions on box cake mix.
4. Allow to cool 5 minutes in the pan. Invert pans on cooling wrack and allow to cool completely.

Raspberry champagne filling
12 oz raspberries- I used thawed frozen raspberries
1/2 cup sugar 1 tsp champagne (you could use water or lemon juice instead)
2 Tbsp cornstach
1 Tbsp raspberry liqueur (optional)

1. In a saucepan combine raspberries, sugar, champagne, cornstarch. Cook over medium heat, stirring frequently until thickened.
2. Remove from heat, stir in raspberry liquer if using. -Note- you can strain the filling to make it seedless, but I liked the seeds. Original recipe with directions can be found here
3. Allow to cool completely.

Raspberry champagne buttercream
Original recipe for champagne buttercream here

2 sticks of butter at room temperature
4 cups confectioners sugar
1/2 tsp vanilla extract
4 Tablespoons champagne
1 Tbsp raspberry preserves
Splash raspberry liquer

1. In mixing bowl, combine butter, sugar, vanilla, champagne. Beat until light and fluffy. Add champagne if needs to be thinned. Add sugar if needs to be thickened.
2. Stir in raspberry preserves. Stir in splash of raspberry liquer.

Assembly

1. Level cakes so they are flat on top.
2. Pipe a dam of frosting on the rim of bottom cake.
3. Fill cake with filling. Invert top layer so bottom of the cake is facing up and place over bottom layer.
4. Frost cake. Decorate.
5. Enjoy!