Cut the angel food cake into 1 inch cubes.
Wash and dice the strawberries into 1/2 inch cubes.
Add the butter, powdered sugar, milk and vanilla to the bowl of a stand mixer. Starting very slowly and gaining speed gradually, mix the ingredients together.
Once all of the ingredients are incorporated, turn them mixer on high and whip for 2-3 minutes.
If the frosting is a bit stiff for your liking, just add a little more milk. If it is too soft, add some more powdered sugar. This buttercream is very forgiving.
To assemble, place a good handful of angel food cake into the bottom of each clear cup.
Top the angel food cake with diced strawberries.
Pipe the buttercream onto the top of the cup.
The cups are ready to be served. These do not need to be refrigerated, and will keep well at room temperature for several hours.