In a mixing bowl, combine the gluten-free all-purpose flour and salt. Add the cold, cubed unsalted butter, blending until it resembles coarse crumbs.

Stir in a beaten egg and enough cold water to form a smooth dough. Wrap in plastic wrap and chill in the refrigerator for 30 minutes.

In a skillet over medium heat, add oil and sauté the onions and bell peppers for about 5 minutes. Stir in the shredded chicken and cumin.

Remove from heat and let cool slightly before adding cheese.

Preheat the oven to 375°F (190°C). Roll out the chilled dough to 1/8-inch thick. Cut circles and place filling on each, sealing edges.

Arrange on a baking sheet, brush with egg wash, and bake for 20-25 minutes until golden brown.