Preheat oven to 350 degrees. Grease 3- 9 inch cake pans.
Cake
Mix all ingredients together until smooth. Pour equal amounts into the cake pans and bake for 35-40 minutes or until toothpick comes out clean.
Remove from cake pans, and cool on a cooling rack before icing.
Icing
Cream softened butter and 1 C of sugar together. Slowly add the rest of the sugar. Add lemon curd, juice, vanilla. Add food coloring to get desired color. Beat until fluffy.
Place first cake layer on icing turntable. Top with 1 jar lemon curd. Top lemon curd with just enough buttercream to cover it. Add second layer and repeat.
Add third layer. Spread a thin layer of buttercream over top and sides as a crumb layer. Refrigerate 5 minutes to set. Remove from fridge and use almost all of buttercream to completely ice the cake. Use the rest of the buttercream to decorate. Make more icing if necessary.