Special equipment: An immersion blender; a pastry bag fitted with a medium tip
Whisk together the flour, granulated and brown sugars, the baking powder, baking soda and salt in a medium bowl. Whisk together the eggs, buttermilk, butter and vanilla in a small bowl. Add the wet mixture to the dry mixture and gently mix to combine. Do not overmix. Let sit at room temperature for at least 15 minutes and up to 30 minutes before using.
Preheat the oven to 200 degrees F. Heat a cast-iron or nonstick griddle pan over medium heat and brush with melted butter. Once the butter begins to sizzle, use 2 tablespoons of the batter for each pancake and cook until bubbles appear on the surface and the bottom is golden brown, about 2 minutes. Flip over and cook until the bottom is golden brown, 1 to 2 minutes longer. If desired, keep warm on a baking sheet in the oven.
Serve a stack of 6 pancakes per person, topped with some of the Pineapple-Mango Syrup and Mascarpone Whipped Cream. Dust with confectioners' sugar. Garnish with fresh mint sprigs, if desired.
Combine 2 cups chopped mango, 2 cups chopped pineapple, the sugar and 2 cups water in a large saucepan, bring to a boil over high heat and cook, stirring occasionally, until the fruit is very soft, about 15 minutes.
Remove the pan from the heat and, using an immersion blender, blend until almost smooth. Add the honey and simmer over medium-low heat, stirring occasionally, until slightly thickened, about 15 minutes.
Strain the mixture into a bowl and add the finely diced mango and pineapple, the orange zest and lemon juice to taste. Keep warm while making the pancakes.
Combine the mascarpone, confectioners' sugar, vanilla and 1/2 cup cream in a medium bowl and whip until soft peaks form; add a bit more heavy cream if not creamy enough. Put in a pastry bag with medium tip.