Cuban Black Beans (Frijoles Negros)

If using dried beans (soaked overnight), drain and rinse. Place in a large pot and cover with 8cm of cold water. Bring to a boil over high heat, then reduce to a steady simmer. Cook for 60-90 minutes until beans are completely tender throughout — they should crush easily between two fingers. Season with salt only when completely soft; salt added before tenderness toughens the skin and extends cooking time significantly. Reserve 2 cups of the bean cooking liquid before draining.

Heat olive oil in a wide, heavy-bottomed pot over medium heat. Add diced onion and green pepper. Cook, stirring occasionally, for 8-10 minutes until completely soft and beginning to turn golden — the onion should be translucent throughout, not just at the edges. Add garlic and cumin. Cook for another 90 seconds, stirring constantly, until the garlic is fragrant and the cumin blooms in the fat, smelling toasty and warm. The sofrito should look like a thick, golden-green jam.

Add the cooked beans to the sofrito pot along with the reserved cooking liquid. Stir to combine and bring to a simmer. Cook uncovered for 20-30 minutes, stirring occasionally, until the liquid has reduced and thickened considerably — it should coat the back of a spoon and look glossy. In the final 2 minutes of cooking, add the vinegar or white wine. Do not cook after adding the vinegar; you want the brightness to be present in the finished dish, not cooked away. Taste and adjust salt.