Preheat the oven to 350°F and line a baking sheet with parchment paper.
Using an electric beater or a whisk, cream together the sugar and butter until fluffy.
1 cup butter, softened (227g), ½ cup granulated sugar (100g)
Mix in the egg yolks and vanilla, then mix in the flour and salt (if using).
2 egg yolks, 1 tsp vanilla extract, 2 ¼ cups all-purpose flour (281 g), ½ tsp salt (if using salted butter, you can skip this)
Lightly beat together the egg whites in a separate bowl. They don’t need to be super fluffy, just mixed together so they’re no longer gloopy.
2 egg whites
Place the finely chopped pecans into a small bowl.
1 cup finely chopped pecans
Scoop about a tablespoon and a half of cookie batter and roll it into a ball between your hands.
Dip the cookie dough ball into the egg whites, then dip it into the pecan pieces.
Place about 8 cookies onto a baking sheet about 2 inches apart, and place the rest of the cookie dough into the fridge.
Using a teaspoon or your thumb or knuckle, make a small indentation into the center of each cookie. In each indentation, put up to a teaspoon of your favorite jam (depending on the size of the indentation). Don’t overfill, though. You don’t want the jam to leak out while it bakes.
½ cup jam
Bake the cookies for 12-14 minutes, then let them cool completely before eating.