- Preheat oven to 350°F (175°C).
- In a large Dutch oven or oven-safe pan, melt butter and olive oil over medium heat.
- Add sliced onions and sauté until tender and browned (about 20-25 minutes).
- Add chopped garlic and sauté for 2-3 minutes until fragrant.
- Arrange sausages in the pan on top of the onions.
- Pour beer and beef stock into the pan, ensuring sausages are almost covered.
- Stir in Dijon mustard, salt, and pepper.
- Bring mixture to a simmer on the stovetop, then transfer to the preheated oven.
- Bake uncovered for 30-40 minutes, or until sausages are cooked through.
- Garnish with chopped parsley, if desired.
Enjoy!
