1 cup (2 sticks/16 TB) salted butter, softened (soft enough that it will give when you lightly press it, but not melted.)
1/2 cup confectioners’ (powdered) sugar, plus 1/4 cup more for dusting
2 teaspoons pure vanilla extract
1/8 tsp table salt
2 cups all purpose flour
1/2 cup thick fruit preserves (i.e., raspberry, blackberry, peach)
Preheat oven to 325°F with rack on middle position. Line a baking sheet with parchment paper.
In the bowl of a stand mixer fitted with paddle attachment on high speed, beat butter and sugar until creamy and light, 2-3 minutes (do not rush this part, as it will determine how your dough turns out.) Add vanilla and salt, scraping down bowl as needed. Switch to medium-low and gently mix in flour, just until combined. Dough should be somewhat sticky. Form into a ball shape, cover, and chill 30-60 minutes.
Roll tablespoonfuls of dough into 1-inch balls. Place dough balls on parchment-lined baking sheets or silicone baking mats. Press down the center of each ball with handle-end of a wooden spatula or finger, making a deep well in the middle – deep but not too wide (it helps to hold the dough ball in palm of hand while forming the well with your finger.)
Fill cookie centers generously with jam/preserves. I use either a very small spoon or a piping bag. Bake 20-25* minutes or until golden brown and puffy. Let cool 5 min. on baking sheet, then gently transfer to finish cooling on wire rack.
When cookies are completely cooled, dust with confectioners’ sugar. Cookies can be kept in airtight container at room temp for a few days.