Chocolate Dipped Brownie Cookies

INGREDIENTS

• 1/2 cup all-purpose flour
• 2 tablespoons dark or dutch-processed cocoa powder
• 1/4 teaspoon baking powder
• 1/4 teaspoon salt
• 8 ounces dark or semisweet chocolate, chopped
• 1/4 cup (1/2 stick) unsalted butter, cut into cubes
• 2 large eggs, room temperature
• 3/4 cup granulated sugar
• 1 teaspoon vanilla extract
• 1/2 cup mini semisweet chocolate chips
• For Dipping:
• 6 ounces dark or semisweet chocolate, finely chopped
• 1 to 2 tablespoons vegetable shortening, as needed
• Rainbow sprinkles