Preheat the waffle iron.
In a bowl, combine the flour,almond meal, cornstarch, baking powder, baking soda, 2 Tbsp sugar and salt. Stir with a wire whisk to combine and make sure that there are no lumps.
Separate the egg and place the egg white in a medium bowl whip until stiff. In another bowl combine the grated carrots, buttermilk, melted butter, egg yolk, and vanilla. Add to the dry ingredients and when all is mixed gently fold in the beaten egg whites. Set aside.
In a small bowl combine the mascarpone, 1 Tbsp sugar and lemon juice. Set aside.
Slice a 2 inch slice from a fresh pineapple, cut in half and remove the peel and core. Slice each half into 4 thin slices. Arrange the slices in a glass baking dish and brush with melted butter. Place under the broiler for 5-10 min watching carefully, till they start to brown at the edges. Remove from the oven and set aside.
Brush the hot waffle iron with oil. With a dipper measure enough of the carrot batter onto the bottom half, not filling to the sides (about 1/2-2/3 cup) so that it bakes without baking over. Carefully remove from the iron when the light turns off and it is baked. (5-8 min) It will be a deep golden brown.
Place on a plate, Add 2-3 Tbsp of the mascarpone in the middle and arrange the a slice of the roasted pineapple on top. Sprinkle with powdered sugar and a bit of finely grated carrot.
Serve with syrup if desired.