Cook the onions
Place a pan over medium-high heat. Add olive oil, diced onion, diced garlic, and sliced squash (use red Kuri squash or butternut squash). Stir and cook for 5 minutes. While the vegetables are cooking, remove the stem of kale. Place in a bowl and cover with hot boiling water. Leave stand for about 3 minutes, then drain.
empanadas vegetarian filling
Add drained kale to the squash in the pan together with pitted black olives and sesame seeds. Stir well and remove from the heat. Leave to cool to room temperature, for about 10 minutes. Then add feta cheese (feel free to use other, similar white cheese) and one egg. Stir to combine. Optionally season to taste with salt and pepper.
bake the puff pastry empanadas
Cut 12 circles out of the puff pastry roll (approx. 6 circles per pastry sheet) using a pastry ring or a small bowl. Place a spoonful of the filling on one side of each circle. Brush the edge of the circle with water. Fold the one side without the filling over the filling. Press together using tines of a fork. Transfer to a large baking sheet lined with parchment paper. Place in the oven on the middle rack. Bake for 25 - 30 minutes at 190 °C or 375 °F.
Serve these vegetarian empanadas warm or cold, along with some homemade yogurt sauce. Enjoy.