Most sugar cookie disappointment is the same disappointment: you cut a perfect snowflake, it goes into the oven, and it comes out as a circle. This dough is built to stop that happening.
Three things do the work. Enough flour that the dough feels firm rather than soft. A full teaspoon of baking powder, which pushes the cookie up instead of out. And a short chill on the tray before baking, so the butter has further to go before it melts.
Why brown sugar
Plenty of cut-out recipes use only white sugar or powdered sugar. Brown sugar caramelises in the oven and gives the cookie an actual flavour rather than just sweetness. It also means you want to bake these until the edges go golden - pulling them out pale wastes the thing that makes them good.
Judging the dough by feel
The flour quantity is not fixed. Altitude, humidity and how warm your butter was all move it. The test is tactile: squish the dough between your hands, and if it gives easily it needs more flour. This is the one part of the recipe you cannot do by numbers alone.
Decorating
These are built as a base for royal icing, which sets hard and holds detail. Bake them, cool them completely, and ice them the next day if you can - a fully cooled, slightly dried surface takes icing far better than a warm one.