Awesome Collard Greens recipe!!

Made this yesterday and It was SO good!!

1 tbsp olive oil
1 tbsp butter
1⁄2 large onion, chopped
1 tsp red pepper flakes
1 clove garlic, finely chopped
1 lb collards, chopped
3 cup vegetable stock
2 tomato, seeded and chopped
1 salt
1 black pepper, freshly ground
Directions
In a large pot over medium heat, heat oil and butter. Saute the onions until slightly softened, about 2 minutes, then add the red pepper flakes and garlic, cook another minute. Add collard greens and cook another minute. Add the vegetable stock, cover and bring to a simmer. Cook until greens are tender, about 40 minutes. Add tomatoes and season with salt and freshly ground black pepper.