1. FOR THE CINNAMON BUNS: Combine brown sugar, 1 tablespoon melted butter, 1/4 cup granulated sugar, cinnamon, cloves, and 1/8 teaspoon salt in bowl; set aside.
2. Whisk flour, baking powder, and 3/4 teaspoon salt together in large bowl. In separate bowl, whisk together milk, yeast, 2 tablespoons melted butter, and remaining 2 tablespoons granulated sugar until yeast dissolves. Stir yeast mixture into flour mixture with rubber spatula until dough comes together (dough will be sticky).
3. Transfer dough to lightly floured counter and knead to form smooth, round ball, about 2 minutes. Roll dough into 12 by 9-inch rectangle with long side facing you. Brush 2 tablespoons melted butter over dough, leaving 1/2-inch border at edges. Sprinkle sugar mixture over butter, leaving 3/4-inch border at top edge, and press lightly to adhere. Roll dough away from you into firm cylinder, keeping roll taut by tucking it under itself as you go. Pinch seam and ends closed. If necessary, gently reshape log to be 12 inches in length with even diameter.
4. Grease 10-inch cast-iron skillet with 1 tablespoon melted butter. Using serrated knife, cut cylinder into 8 pieces and arrange cut side down in prepared skillet. Cover buns loosely with plastic wrap and let rise for 30 minutes.
5. Adjust oven rack to middle position and heat oven to 350 degrees. Brush tops of buns with remaining 2 tablespoons melted butter, transfer skillet to oven, and bake until buns are well browned and filling is melted, 25 to 30 minutes, rotating skillet halfway through baking. Using potholders, transfer skillet to wire rack and let buns cool for 10 minutes.
6. FOR THE GLAZE: Whisk all ingredients together in bowl until smooth. Being careful of hot skillet handle, spread glaze evenly over buns. Serve.