In a large mixing bowl, whisk together the all-purpose flour and salt. Cut in the cold vegan butter until the mixture resembles coarse crumbs. Add the apple cider vinegar and cold water gradually, mixing until a dough forms. Knead gently, then wrap in plastic wrap and refrigerate for 30 minutes.

Heat olive oil in a skillet over medium heat. Sauté the diced onion and minced garlic for about 3–4 minutes until translucent. Add the diced carrot, celery, and red bell pepper, cooking for an additional 5 minutes. Stir in the cooked lentils, tomato paste, smoked paprika, cumin, and chili flakes. Mix well and cool.

Once the dough has chilled, divide it into 10 equal portions. Roll each portion into a circle about 5 inches in diameter.

Place a generous spoonful of filling onto one half of each circle. Fold the dough over to create a half-moon shape and crimp the edges to seal. Arrange on a baking sheet and brush tops with plant-based milk.

Preheat your oven to 375°F (190°C). Bake empanadas for 25–30 minutes until golden brown.