Preheat the oven to 350 degrees Fahrenheit and set your mason jars to the side.

Make cake batter according to box directions.

Pour the batter into the Mason jars, filling a little less than half full.

Place the jars on a baking sheet and bake for 18 minutes.

Allow to cool completely.

Cream the butter, vanilla and powdered sugar in a mixing bowl.

Slowly add the milk until desired consistency of the icing is reached.

Ice the tops of cakes.

Sprinkle with candy decorations and place a chocolate bunny on the top of each.