Costa Rican gallo pinto (black beans and rice)

INGREDIENTS

2 cups

cooked black beans, plus 3/4 cup bean cooking liquid (can be made days in advance)

3 cups

cooked long-grain white rice, cooled (can be made days in advance)

1 tbsp

vegetable oil

1/2

onion, diced

bell pepper, diced (in Costa Rica, this would be a green pepper, but I love the red)

1/2 cup

diced celery

large cloves garlic, minced

1 tsp

dried thyme leaf

1/2 tsp

kosher salt, or more to taste

1/2 tsp

fresh black pepper, or more to taste

Chopped cilantro for garnish (optional)