Butter and Jam Thumbprints

INGREDIENTS

• 1 large egg
• 1/2 vanilla bean, seeds scraped from pod, or 1/8 teaspoon vanilla bean paste or 1 teaspoon pure vanilla extract
• 1/2 teaspoon baking powder
• 3/4 cup unsalted butter (1 1/2 sticks), softened
• 2/3 cup sugar, plus more for rolling
• 1/2 teaspoon fine salt
• 1 3/4 cups all-purpose flour
• 1/3 cup raspberry, cherry or strawberry jam