Southern-style collard greens A recipe from <a href="https://www.wefacecook.com/international/cuisine/US">US</a>

Ingredients

• 1 tablespoon olive oil
• 1 tablespoon butter
• 1/2 large onion, chopped
• 1 teaspoon red pepper flakes
• 1 clove garlic, finely chopped
• 1 pound collard greens, chopped
• 3 cups vegetable stock
• 2 tomatoes, seeded and chopped
• Salt and freshly ground black pepper