01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - Heat olive oil in a skillet over medium heat. Sauté the garlic for 30 seconds, then add the chopped spinach and cook until wilted, about 2 to 3 minutes. Remove from heat and let cool slightly.
03 - In a mixing bowl, combine the cooled spinach with crumbled feta, cream cheese, black pepper, and nutmeg. Stir until evenly blended.
04 - Roll out the gluten-free puff pastry on a surface lightly dusted with gluten-free flour. Spread the spinach and feta mixture evenly over the pastry, leaving a 1/2-inch border along one long edge.
05 - Starting from the long side, gently roll the pastry into a tight log. Brush the bare edge with beaten egg and press gently to seal.
06 - Cut the log into 16 even pieces. Place each pinwheel cut side up on the prepared baking sheet, spacing them about 1 inch apart.
07 - Brush the tops of each pinwheel with the remaining beaten egg for a golden finish.
08 - Bake for 20 to 25 minutes until puffed and golden brown. Allow to cool slightly before serving warm or at room temperature.