key lime cupcakes

found these on a blog I follow and they look so good I am going to have to make them!
Key Lime Cupcakes

½ C. butter, softened
1 C. sugar
3 eggs
1 C. milk
1 C. flour
1 (14 oz.) Can sweetened condensed milk
10 graham cracker squares, crumbled
1 t. baking soda
1 t. baking powder
1/8 t. salt
5 egg yolks
½ C. lime juice

è Start by creaming your butter and sugar until it is light and fluffy. Add the 3 eggs, one at a time.
è In a medium sized bowl, shift together the flour, baking soda, baking powder and salt. Mix in the graham cracker crumbles.
è Slowly add the dry ingredients, and the milk, to the butter mixture. Make sure you alternate between the dry ingredients and the milk. (dry-milk-dry)
è In a separate bowl, mix the egg yolks, condensed milk, and lime juice. Pour into your batter and stir slightly.
è Fill cupcake liners ¾ full and bake for 15-20 minutes at 350.

For the frosting, I made a basic cream cheese frosting with a little lemon extract.

Cream Cheese Frosting:
1 8 oz package softened cream cheese
¼ C. soft butter
1 t. lime or lemon extract
4 C. Powdered Sugar

è Mix the cream cheese and butter until combined.
è Add the sugar and extract slowly. Beat on high until fluffy.