How to Make It
In a small saucepan, warm the milk over moderate heat, about 2 minutes. Stir in the yeast until dissolved. In the bowl of a standing mixer fitted with the dough hook, mix the 3 cups of flour with the granulated sugar. With the mixer at medium speed, pour in the warm milk. Add the butter, cardamom, salt and 1 of the eggs. Mix until a smooth dough forms, about 8 minutes.
Cover a large baking sheet with parchment paper and sprinkle with flour. Roll the dough into 8 balls. Place the dough on the prepared baking sheet and wrap the sheet with plastic wrap. Set aside in a warm place until the balls have doubled in size, about 2 hours.
Preheat the oven to 375°. Bake the buns for about 10 minutes, rotating the pan halfway through, until golden brown. Meanwhile, in a small bowl, whisk the remaining egg with 2 tablespoons of water. Immediately brush the hot buns with the egg wash, then transfer to a rack to cool, about 30 minutes.
In a bowl, using an electric mixer, beat the almond paste with 3 1/2 tablespoons of water until creamy. In another bowl, beat the heavy cream until stiff.
Using a small paring knife, cut a deep 1 3/4-inch round plug out of the top of each bun, making sure not to cut through the bottoms; reserve the plugs. Fill the buns with the almond paste and top with some whipped cream. Replace the plugs. Sprinkle with confectioners' sugar and serve.