Leave out two sticks of unsalted butter to soften to room temperature. Butter softening usually takes about 30 minutes. You can tell the butter is soft enough by gently pressing your finger down on it through the wrapping. If your finger makes an impression, the butter is soft enough to work with.

Add the butter to a medium-sized mixing bowl and mix in one and one-half to two teaspoons of vanilla extract. Use a large wooden spoon to combine them or set your electric beater to low speed to mix the ingredients until the batter is smooth and has a light and fluffy texture. Add an extra teaspoon of vanilla extract to the batter for extra-sweet frosting. You can exchange a half-teaspoon of almond extract for every teaspoon of vanilla extract for a sweeter and nuttier flavor.

Powdered sugar tends to absorb moisture from the air and form clumps. To keep your buttercream frosting clump-free, pour your powdered sugar into a sifter and sift your sugar into a new bowl. Scoop out four cups of sifted powdered sugar and add it gradually to your vanilla and butter mixture, beating on low speed until the batter is smooth and creamy.

Be sure to scrape any residual ingredients off the sides and bottom of the bowl with a spoon and add these ingredients back into the batter. Incorporate the ingredients by beating again with the electric beater on low speed for one minute. The batter may look somewhat dry when fully mixed.

Gradually add two tablespoons of milk to your frosting batter. Beat on medium to high heat for about three minutes or until the frosting is thick and creamy. If the mixture still seems slightly dry after mixing, add in a small amount of milk and beat again until the buttercream frosting reaches the desired consistency.

The frosting itself is naturally white, so if you want pink, blue or some other hue of buttercream, you'll need to add some food coloring. After you mix in the milk, add a few drops of food coloring in your preferred shade and stir it in with a spoon. The color should distribute evenly throughout your frosting. If the shade seems a tad light, add an additional drop of food coloring and mix again until it reaches the desired hue.

If your buttercream breaks, it means some of the ingredients have separated, possibly due to temperature differences. Don't give up on your frosting if it falls apart. Instead, keep stirring for a few minutes. It will likely come back together on its own, re-absorb any loose liquid and be perfectly suited to top your treats.

Spoon your buttercream frosting onto the center of the treat in thick dollops to start. Then, spread the frosting outward with a butter knife or offset spatula. Add more frosting to the top as needed and continue to spread over the surface area of your cake, cupcake or other dessert of choice. Smooth the frosting evenly over the top and sides with the edge of your knife or spatula.

For detailed designs and other precise decorating, you'll likely need to pipe the frosting through a pastry bag. A pastry bag is a device that is held in one hand and squeezed near the tip at the other, allowing a thin amount of the buttercream through that you can control by squeezing and releasing the bag.