My boyfriend will be turning 21 next week and it usually takes me awhile to plan a package for him. I came across this idea for cupcakes on the Cupcake Project blog. I had never heard of baking cupcakes right into mason jars (jam jars) and shipping them that way! I was never able to ship cupcakes before knowing the frosting would get completely ruined. I asked him what kind of cake he liked and his answer was funfetti cake. Funfetti cake just like the stuff you buy in a box at the store. I knew the secret to the funfetti cake was to use the colored jimmies in the batter. Easy.
I pulled out my Better Homes and Gardens cookbook to get a white cake recipe and found a vanilla buttercream frosting recipe off of bestcupcakerecipes.blogspot.com. I have never made white cake or vanilla buttercream from scratch before. This was a first for me and I was very excited!
For the white cake:
4 egg whites
2 cups all-purpose flour
1 tsp baking powder
1/2 tsp baking soda
1/2 tsp salt
1/2 cup butter or shortening, softened
1 3/4 cups sugar
1 tsp vanilla
1 1/3 cup buttermilk
Allow the egg whites to reach room temperature for 30 minutes. Grease and lightly flour your cake pan and preheat oven to 350 degrees Fahrenheit. In this case, I made sure to wash the jars and lids with warm soapy water and allowed them to dry. I did not grease them.
In a medium bowl, mix together the flour, baking powder, baking soda, and salt; set aside.
In a separate bowl, beat butter on high with an electric mixer for 30 seconds. Add sugar and vanilla and beat until well combined. Add the egg whites, one at a time, beating well.
Alternately add flour mixture and buttermilk to butter mixture, beating on low. Lastly, add in 1/4 cup of your rainbow sprinkles. Fold into the batter.
Spread batter into your prepared pan or glass jars. Bake for 30 minutes, turning the pan halfway through. Allow to cool completely before frosting. Careful when baking in the glass jars. I kept my jars on a cookie sheet while baking to make it easier for me to take them in and out of the oven.
For the buttercream frosting:
1 cup unsalted butter, softened (2 sticks)
6 to 8 cups powdered sugar
1/2 cup milk
1 1/2 tsp vanilla extract
In a large bowl, beat the butter on high with electric mixer until smooth and creamy. Add 4 cups of sugar, the milk and vanilla extract until well combined.
Add 2 more cups of the sugar on low until fluffy. Add the remaining 2 cups until it reaches the desired consistency for your cake. Frost cake or store frosting, covered, in the refrigerator. I stored it in the fridge for about 30 min before I frosted the cupcakes to make sure it was thick enough for piping.
When I was ready to frost the cupcakes, I took a sturdy ziploc bag and scooped up a bunch of my frosting into one side of the bag. Cutting off the tip, I squeezed the frosting onto the cupcakes in a spiral. You can also smooth on the frosting with a knife if you prefer to skip the bag method. Don’t forget the sprinkles on top!
Keep your cake or cupcakes in an airtight container in the refrigerator. If you’re shipping your jarred treat, I suggest freezing them before shipping them off to make sure the buttercream doesn’t melt.