Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper.
Cream the butter and sugar with a mixer until fluffy, about 1-2 minutes.
1 cup unsalted butter (2 sticks), room temperature, ⅔ cup sugar
Add the egg yolks, maple extract, and salt. Beat until full combined, about 30 seconds to 1 minute.
2 egg yolks, 1 tablespoon maple extract, 1 teaspoon salt
Add the flour and beat until the mixture forms large crumbs. (If you aren't getting large crumbs, add a little more flour and mix until you do.) Then knead with your hands until the dough is easily rolled into a ball.
2 ⅔ cups all-purpose flour
Roll 1 tablespoon portions of the dough into balls and place on the baking sheet, about ½ inch apart.
Using your thumb, make a deep impression in the middle of each ball. Bake for 10 minutes until the bottoms start to brown slightly.
Let cool completely on the baking sheet.
In a medium bowl, combine the powdered sugar, maple syrup, and water. If the icing becomes too thick, add a little extra water to thin it. You should be able to feel a little resistance when stirring but it shouldn't be completely stiff.
2 cups powdered sugar, ¼ cup maple syrup, 2 tablespoons water
Place the icing in a frosting bag and snip a small hole in the corner. Use it to fill each cookie impression with the icing by starting in the middle and filling in to the edges with a circular motion.
Allow the cookie to sit for a few minutes for the icing to set.
Don’t overfill the impressions. The icing will settle on its own and may look like more than you realize when filling.
Use a toothpick to adjust the icing into place, if need be. I used it to ensure the edges were all filled in to get that pretty and perfect circle.
If you don’t want to use your thumb, try using a ½ teaspoon (the back of it) to make the impressions.
If you create larger cookies, use more dough for each cookie and be sure to adjust the cooking time. These cookies are about 2 inches in size.
Be sure to make your impression deep enough as it will rise just a touch during the baking process and might disappear if made too shallow.
There’s no need to move these cookies to a cooling rack once they’re pulled from the oven.