1. Preheat your oven to 375°F or 190°C. Line a baking sheet with parchment paper to prevent sticking.

2. Roll out the gluten-free croissant dough until it reaches a thickness of about 1/4 inch or 6 mm. Cut the dough into 8 equal-sized pieces, making sure they're as uniform as possible.

3. To make the feta cheese filling, combine 150g or 5.3 ounces of crumbled feta cheese, 2 tablespoons of grated Parmesan cheese, 1 tablespoon of chopped fresh basil, 3 tablespoons or 45g of chopped pine nuts, and 1 minced garlic clove in a bowl. Mix well until all the ingredients are fully incorporated.

4. For the ham and cheese filling, mix 2 slices of diced ham and 1/4 cup or 60g of grated cheddar cheese in a separate bowl until well combined.

5. To make the spinach and feta filling, combine 1/2 cup or 15g of chopped fresh spinach, 50g or 1.8 ounces of crumbled feta cheese, and 1 minced garlic clove in another bowl. Mix until the spinach is evenly distributed throughout the cheese.

6. Place a tablespoon of each filling on one half of the dough pieces, leaving a 1/2 inch or 1 cm border around the edges to prevent the filling from escaping during baking. Fold the other half of the dough over the filling and press the edges to seal. Use a fork to crimp the edges and create a decorative border.

7. Place the croissants on the prepared baking sheet, leaving about 1 inch or 2.5 cm of space between each one to allow for even baking.

8. Brush the tops of the croissants with a beaten egg and sprinkle with sesame seeds for added flavor and texture.

9. Bake the croissants for 20-25 minutes or until they're golden brown. Serve warm or at room temperature, depending on your preference.