Prepare the grill for indirect cooking over medium heat (350° to 400°F).
Generously grease a 10-inch metal pie pan with softened butter. Sift the flour and baking powder into a large bowl. Add the granulated sugar, salt, cinnamon, and cloves and whisk well. Cut the 5 tablespoons of cold butter into 1/2-inch pieces and add to the bowl, mixing with your fingertips until you have a coarse meal. Whisk the milk, eggs, and vanilla and add to the bowl. Mix until well combined but with a few lumps. Pour the batter evenly into the pie pan and smooth the top.
Core and then slice the apple lengthwise into ⅛-inch-thick slices. Arrange the slices on top of the batter around the outer edge of the pie pan, like petals of a flower, overlapping them slightly. In a small bowl mix the brown sugar and cinnamon. Sprinkle evenly over the top of the apples and batter.
Grill over indirect medium heat, with the lid closed, for 20 minutes. Rotate the pan 90 degrees. Continue grilling, with the lid closed, until a wooden toothpick inserted in the center comes out clean, 15 to 20 minutes more. Cool on a wire rack for 15 minutes. Cut into wedges and serve at room temperature with whipped cream, if desired.
Grill over medium heat, with the lid closed, for 20 minutes. Rotate the pan 90 degrees. Continue grilling, with the lid closed, until a wooden toothpick inserted in the center comes out clean, 15 to 20 minutes more. Cool on a wire rack for 15 minutes. Cut into wedges and serve at room temperature with whipped cream, if desired.
