Frosted Brown Sugar Pop Tart Bars

Bahan-bahan (16 porsi)

• 2 1/2 cups all-purpose flour
• 1/2 cup dark brown sugar
• 2 sticks (1 cup) cold salted butter, shredded
• 1 tablespoon vanilla extract
• 1 cup dark brown sugar
• 1 tablespoon all-purpose flour
• 1 tablespoon ground cinnamon
• 2 tablespoons salted butter, melted
• 1/4 cup apple butter
• 2 teaspoons vanilla extract
• 1 teaspoon salt
• 2 cups powdered sugar
• 1/4 cup maple syrup
• 1 tablespoon vanilla extract
• 1 teaspoon ground cinnamon
• coarse salt or sugar, for sprinkling ((optional))