Use a handheld mixer or a food processor with a whisk attachment to do this. It will be faster. You can also use a whisk or a wooden spoon in a pinch. Use salted butter if you want less sweet buttercream. Adding the sugar a little bit at a time will allow the butter to absorb the sugar better. You'll get a smoother cream in the end.  If you are using a handheld mixer, start at a slower speed. This will keep the sugar from flying out. Try to sift the sugar into the butter. This will get rid of clumps. Keep mixing until the color and texture are even and smooth. There should be no streaks, swirls, or lumps. It will take about three minutes. If you are using a handheld mixer, you can increase the speed after the sugar and cocoa powder are mixed in. Chocolate buttercream tastes wonderful, but you can improve your buttercream by giving it a hint of another flavor. Be sure to mix it thoroughly to evenly distribute the flavor. Here are some ideas that work well with chocolate:  To give the buttercream a hint of sweetness, add 1 teaspoon of vanilla extract. To give the buttercream a hint of extra flavor, add ½ teaspoon of almond extract. To cut the sweetness and give the buttercream a richer flavor, add in a splash of brandy or rum. If the buttercream is too thin, add some more sugar. If the buttercream is too thick, add some more milk. Start with a tablespoon or two at a time, mix, and add more as needed.
ضعي الزبدة في وعاء واخفقيها حتى تصبح هشة. اخلطي نصف كمية سكر الحلويات/المطحون مع الزبدة. اخلطي الكمية المتبقية من السكر والحليب وزبدة الكاكاو. جرّبي أن تضيفي بعض النكهات. تحققي من القوام واضبطيه وفقًا لتفضيلاتك الشخصية.