Preheat the oven to 350°F. Unless you are using nonstick pans, line 2 sheet pans with parchment paper.
To keep the balls the right size, weigh 1 ounce of dough or spoon out 2 tablespoons, and roll it into a ball. Use it as a model to make the others the same size. Arrange them on the prepared sheet pans. Press them down with the heel of your hand to flatten them into 2-inch rounds. Press in the center to make an indentation - don't poke all the way through the cookie - and fill the indentation with 1/2 teaspoon jelly or enough to come up to the top of the indentation. Don't add too much or it will run down the sides of the cookies in the oven.
Bake for about 20 minutes, or until very pale brown around the edges. Let cool until set and then transfer to cooling racks, or cool in the pans set on racks. Store tightly sealed in an airtight container for up to 1 week.