Bring to a boil, cover, reduce the heat, and simmer until the pumpkin is very tender, about 20mins. Uncover and cook until the liquid evaporates and the mixture thickens. Let cool. This is not a smooth mixture.
Preheat the oven to 190°c / 375°f. Line 2 large baking sheets with parchment paper or lightly grease.
Divide the dough into 1 1/2 inch balls (about 2 ounces). On an oiled / floured surface, roll each ball into a 4 inch round about 1/8 inch thick.
Incorporate about a teaspoon of butter into the dough circle, pushing and kneading it in but maintaining the circle.
Place heaping tablespoonful of filling n the center of each round.
Gather the edges from 3 sides and ring together toward the center to form a triangle, pinching the edges to seal.