It is sometimes so hard to find a good recipe for buttercream. I finally figured it out! I hope this helps!
Step 1: Butter
Take 3 sticks (1 1/2 cups) butter out of the fridge and allow to sit until they are very soft. Not melted, though.
Step 2: Sugar
When butter is soft, add 5 cups powdered sugar. Whisk together with butter until smooth. The consistency should be very thick. If you want thick frosting for decorating intricately, stop here. But if you want buttercream to frost a cake, keep reading.
Step 3: Vanilla
Add 1 teaspoon vanilla extract.
Step 4: Milk
Add 2 - 3 tablespoons milk. Whisk until smooth.
Step 5: Dye
If you want to dye, now is your time. Otherwise, store in the fridge for a few days or in the freezer for a few weeks.
Step 6: Enjoy Decorating!
There is so much you can do with frosting, so have fun! Above are a few cakes I made recently using this recipe. Have fun and experiment!