Preheat the oven to 375°F (190°C) and line a large baking sheet with parchment paper.

In a large mixing bowl, combine the self-rising flour and Greek yogurt. Stir until a shaggy dough forms, then knead on a floured surface for 2-3 minutes until smooth.

In a non-stick skillet over medium heat, scramble the egg whites until fully set. Season with salt and pepper. Remove from heat and stir in the cooked turkey sausage.

Divide the dough into 12 equal pieces. Roll each piece into a rectangle approximately 3 by 5 inches.

Lay 6 dough rectangles on the prepared baking sheet. Distribute the egg and sausage mixture evenly onto the center of each, then top with shredded cheddar cheese, leaving a 0.5-inch border around the edges.

Place the remaining 6 dough rectangles over the filling. Use a fork to crimp and seal the edges firmly.

Whisk the whole egg with 1 teaspoon of water and brush the tops of each pop-tart generously with the egg wash.

Sprinkle each tart with everything bagel seasoning.

Bake for 18 to 22 minutes, or until the pastry is golden brown and firm to the touch.

Cool on a wire rack for 5 minutes before serving.