Braised Onion Sauce

Ingredients

• 6 tablespoons unsalted butter (3 ounces), divided
• 4 medium onions, chopped
• 1/2 teaspoon kosher salt, divided, plus more to taste
• 3 large garlic cloves, thinly sliced
• 1/4 cup tomato paste
• 1/2 cup dry white wine or white cooking wine
• 3 cups vegetable stock, plus more as needed
• 2 bay leaves
• 1 teaspoon high-quality balsamic vinegar
• 1/4 teaspoon black pepper, plus more to taste

Preparation

• Melt 1/4 cup butter in a large Dutch oven over medium heat. Add onions and 1/4 teaspoon salt; cook, stirring occasionally, until onions are soft and translucent, about 10 minutes.
• Add garlic; cook, stirring often, until fragrant, about 1 minute. Add tomato paste; stir to coat onions. Cook, stirring constantly, until tomato paste slightly darkens, about 2 minutes.
• Stir in wine; bring to a simmer over medium heat. Simmer, undisturbed, 3 minutes.
• Add stock, bay leaves. Return to a simmer over medium heat.
• Reduce heat to medium-low; simmer, stirring occasionally, until liquid is absorbed and mixture reaches a jammy consistency, 1 hour and 30 minutes to 2 hours. If needed, after about 1 hour, stir in additional stock, 1/2 cup at a time, to prevent burning.
• Remove and discard bay leaves. Add balsamic vinegar and remaining 2 tablespoons butter; stir until butter melts.
• Season with salt and pepper to taste. Remove sauce from heat.

Serve with large pasta (e.g. jumbo shells) and grilled meat (e.g. pork tenderloin).