Heat oven to 325°F. Grease and flour a 4-cup and a 2-cup oven-proof measuring cup.
Place paper baking cup in each of 7 regular-size muffin cups.
Make cake mix as directed on box using water, oil and eggs.
Add almond extract and enough green food colour to make light green batter; blend well. Fill 4-cup measuring cup with 2 cups batter.
Fill 2-cup measuring cup with 1 cup batter.
Divide remaining batter into muffin cups.
Bake cupcakes 20 to 25 minutes, 2-cup measuring cup 30 to 35 minutes and 4-cup measuring cup 35 to 40 minutes or until toothpick inserted in centre comes out clean.
Cool 10 minutes; remove cupcakes from pan and cakes from measuring cups to cooling rack. Cool completely, about 1 hour.
Meanwhile, in large bowl, beat butter and icing sugar with electric mixer on low speed until blended.
Mix in 3/4 cup milk, vanilla and enough green food colour to make desired green coloured frosting. If frosting is too thick, beat in more milk, a few drops at a time.