Jenny Rosenstrach’s Shortcut Minestrone – Rancho Gordo

Ingredients

• 2 tablespoons unsalted butter
• 1 tablespoon extra-virgin olive oil, plus more for drizzling
• 1 large yellow onion, thinly sliced
• Kosher salt and freshly ground black pepper to taste
• 1 garlic clove, minced
• ¼ teaspoon red pepper flakes
• 1 tablespoon tomato paste
• 2 (15-ounce) cans white beans, such as cannellini, drained and rinsed
• 4 cups vegetable broth, homemade or Better Than Bouillon
• 1 (14.5-ounce) can diced tomatoes, undrained
• 1 (12-ounce) bag shredded slaw vegetables (or 5 cups of your own shredded vegetables such as cabbage, broccoli, carrots, cauliflower, etc.)
• 1 tablespoon sherry vinegar, plus more to taste
• Handful of fresh basil leaves, torn, for serving
• Freshly grated or shaved Parmesan cheese, for serving