Blackberry Sage Thumbprints

Ingredients (10)

• 2 cups all purpose flour
• 2/3 cup fine grain cornmeal
• 1 1/2 teaspoons dried sage, crushed
• 1/4 teaspoon baking powder
• 1 cup (2 sticks) butter,
• 1 cup packed light brown sugar
• 2 large egg yolks
• 1 1/2 teaspoons finely grated lemon zest
• 2 teaspoons vanilla extract
• 3/4 cup seedless blackberry jam