Growing up, those tubes of slice-and-bake cookies from the grocery store were the extent of my baking. It was the first treat I learned how to bake myself. When I'd slice the dough, however, it would often flatten on one side and become far from the perfect cookies pictured on the package. Now, as I make my own slice-and-bake cookies, I've learned a thing or two to help get that perfect round shape without fuss.
The Easy Way
Start by placing a generous piece of plastic wrap on a work surface. Shape the dough into a 6 1/2-inch-long log that is about 1 1/2 inches in diameter. Place the log on a sheet of plastic wrap at a long end, then roll it up to completely wrap it in plastic and twist and tie the ends together.
Place it in the freezer for about an hour to firm up and then when you're ready to slice, unwrap the log and trim the rounded ends. Cut the log into rounds, rotating the log a quarter turn after every slice. Rotating the log as you go ensures one side won't get squished down as you slice and you won't ruin that nice round shape.
The Fun Way
If you're about to toss the cardboard center of a roll of paper towels, hold off for a few so you can also try this method. Slit the roll open along the length with a pair of scissors, then place your plastic-wrapped log of cookie dough inside it. Chill the dough right in the tube, which acts as a mold, and then when you go to slice it, keep the dough in the mold, pushing it out from the opening as you slice, so that the tube keeps the bulk of the cookie dough in a circular shape even if it softens.