Preheat oven to 375°F (190°C) and lightly grease a 12-cup muffin tin with butter.

In a large mixing bowl, combine flour and salt. Cut in cold butter using a pastry cutter or fork until mixture resembles coarse crumbs.

Add cold milk gradually, mixing until dough comes together. Do not overmix. Wrap in plastic and refrigerate for 15 minutes.

Meanwhile, heat olive oil in a skillet over medium heat. Sauté diced onions until translucent, about 5 minutes.

Add minced garlic and cook for 1 minute until fragrant.

Drain and chop hearts of palm into small pieces. Add to the skillet and cook for 3 minutes.

Stir in cream cheese, heavy cream, chopped parsley, salt, black pepper, and paprika. Mix until well combined and creamy. Remove from heat and let cool slightly.

Remove dough from refrigerator and divide into 12 equal portions. Roll each portion into a ball, then flatten and press into muffin cups, creating a small shell with raised edges.

Spoon the palmito filling evenly into each pastry shell, filling about 3/4 full.

Optional: Roll out remaining dough scraps and cut small circles to place on top of each empadinha as a lid, pressing edges to seal.

Brush tops with beaten egg for golden color.

Bake for 25-30 minutes until crust is golden brown and filling is bubbling.

Let cool in pan for 5 minutes before transferring to a wire rack.

Serve warm or at room temperature.