Prepare the grill for indirect cooking over medium heat (350° to 450°F).
Generously grease a 10-inch metal pie pan with butter. Sift the flour and baking powder into a large bowl. Add the sugar, salt, cinnamon, and cloves and mix well. Cut the 5 tablespoons of butter into small 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 well. The batter should be well combined but still have some lumps. Pour the batter evenly into the pie pan.
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 skewer 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.