Melt 2 tablespoons butter in a small skillet over medium heat. Add spinach and sauté 2–3 minutes until fully wilted. Transfer to paper towel, press out excess liquid, and let cool. Chop roughly.
In a small bowl, whisk the egg. Fold in ricotta and Parmesan, then stir in the cooled spinach.
Unroll pie crust and cut eight 4-inch rounds. (Skip if using discos.)
Place 1 tablespoon of filling slightly off-center on each round, leaving a ½-inch border. Moisten the edge with water, fold into a half-moon, press the seam with your fingers, then crimp with a fork.
Preheat air fryer to 350°F for 3 minutes. Brush empanadas with melted butter.
Arrange in a single layer in the basket. Air fry 8–10 minutes, flipping halfway, until deep golden brown. Work in batches as needed.
Cool 2 minutes, then serve warm.