To make empanadas, let pie dough rest at room temperature until it unrolls easily onto a lightly floured surface, about 30 minutes.

Preheat the oven to 375°F. Line a baking sheet with parchment paper.

In a blender or food processor, combine black beans, cilantro, lime juice and 1 tablespoon water and blend until smooth.

Transfer filling to a bowl and fold in cheese.

Using a large (3-inch) circle cutter, cut out 7 rounds from each piece of pie dough.

Dampen your fingertips with water and moisten the edge of each round.

Spoon a heaping tablespoon of filling into the middle of the round.

Gently fold each round in half, taking care to not squish the filling from the center.

Using a fork, gently press the edges of the empanada closed and transfer to the prepared pan.

Bake until golden brown, about 25 minutes. Let cool slightly before serving.

Meanwhile, make salsa verde: Heat oil in a medium saucepan over medium-high heat.

Add tomatillos, onion, serrano chile and garlic.

Reduce heat to medium-low and cook, stirring occasionally, for 5 minutes.

Transfer tomatillo mixture to a blender or food processor, add cilantro and salt and blend on low, increasing speed until evenly blended.

Let cool slightly and serve with empanadas; refrigerate remaining salsa for another use.