"My Andalucian landlord passed me this recipe from the south of Spain, land of wine and olive oil and tauromaquia. Stewed for hours in red wine, this oxtail dish has the perfect balance of tanginess and meatiness."
Heat 3 tablespoons olive oil in a Dutch oven over medium-high heat; brown oxtail, about 3 minutes per side.
Heat 2 tablespoons olive oil in a large skillet over medium heat; add onion, carrots, leek, and garlic. Cook and stir until tender and beginning to brown, about 5 minutes.
Pour vegetable mixture into Dutch oven with the oxtail. Add red wine, tomatoes, thyme, and bay leaves; stir to combine. Bring stew to a boil until alcohol from red wine evaporates, about 3 minutes. Add enough water to cover, bouillon cube, salt, and pepper. Reduce heat to low and simmer, stirring occasionally, until meat falls away from bone, about 4 hours. Remove oxtail from stewing liquid.
Melt butter in a skillet over medium heat. Whisk in flour to form a thick paste; cook and stir until flour turns light brown, about 15 minutes. Whisk in stewing liquid and bring to a boil; simmer until thickened to stew consistency, 2 to 3 minutes. Pour stew over the oxtail to serve.