Prepare the Peach Filling: In a medium saucepan, combine the chopped peaches, 1/4 cup sugar, cornstarch, cinnamon, and lemon juice. Cook over medium heat, stirring occasionally, until the mixture thickens and begins to bubble (about 5-7 minutes). Remove from heat and let it cool completely, about 20 minutes.

Preheat the oven to 375°F (190°C). Lightly grease a standard 12-cup muffin tin.

Prepare the Dough: Unroll the two sheets of croissant dough. Gently separate the triangles. Using a rolling pin, lightly flatten each triangle. Brush both sides lightly with melted butter.

Assemble the Cruffins: Stack 3-4 buttered triangular pieces on top of each other, slightly overlapping them in a circular fashion. Gently press the stack into the muffin cup, allowing the edges to fan out slightly over the rim. Repeat for all 12 cups.

Fill and Bake: Spoon about 1-2 tablespoons of the cooled peach filling into the center of each dough-lined muffin cup. Sprinkle the tops generously with the cinnamon-sugar mixture.

Bake for 18-20 minutes, or until the croissant edges are golden brown and flaky. Let the cruffins cool in the tin for 5 minutes before carefully transferring them to a wire rack to cool completely.

Serve warm or at room temperature, dusted with additional powdered sugar just before serving.