Make cake mix
Prepare white cake mix as directed on box. Seperate into 4 bowls and color cake batter pink, yellow, blue and purple. Bake in lined cupcake pan. Cool completely.
Prepare icing: 1 cup of butter mix, add 2lbs of powedered sugar and mix. Add vanilla, milk - mix a little at a time to reach desired consistency.
Cut cupcakes accordingly.
Fill icing bag
Fill icing bag with the icing you created in step 2.
Layer the cut up cupcakes and incing in jars. Refer to picture for example.
Top with Spring colored sprinkles.