Make sure your starter is active and bubbly before using it. Also, try folding the dough instead of kneading it.

Baking soda is a base that needs an acid to activate, while baking powder contains both an acid and a base.

How does gluten affect the texture of baked goods?

A hot spatula can also help in smoothing out the buttercream.

How do I know if my yeast is still good?

Start with a good set of measuring cups and spoons, a quality mixing bowl, and a reliable oven thermometer."

I always use the spoon-and-level method to avoid packing the flour too tightly. Works like a charm!