Kittencal's Chocolate Buttercream Frosting/Icing

I got this recipe from Julie Carroll. It is so good!
Choose the amount of cocoa powder you desire for either a light, medium or dark frosting --- this frosting *freezes* very well so double the recipe and freeze one batch for next time --- *NOTE* for an ultra creamy fluffy milk chocolate frosting add in 1 to 1-1/2 cups thawed Cool Whip topping at the end of mixing the frosting and beat on low speed until blended ---
5 min | 5 min prep
SERVES 24 , 2 cups
• 1/2 cup butter, softened (you can use margarine but the flavor will not be the same)
• 2 2/3 cups confectioners' sugar
• 1/3 cup half-and-half cream or milk (can use unwhipped whipping cream in place of half and half)
• 1 1/2 teaspoons vanilla
CHOOSE ONE OF THE FOLLOWING
• 1/3 cup unsweetened cocoa powder, sifted (for light)
• 1/2 cup unsweetened cocoa powder, sifted (for medium)
• 3/4 cup unsweetened cocoa powder, sifted (for dark rich)
1. Cream the butter in a small bowl.
2. Blend in the cocoa powder (the amount desired for a light, medium or dark flavor), vanilla, confectioners sugar, alternately with the cream.
3. Beat with an electric mixer, until the desired texture is achieved.
4. **NOTE** because of the additional cocoa powder more cream may have to be added in to reach desired consistency.