Preheat oven to 350. Break up croissants into bite sized pieces and top with thin slices of butter. Bake for about 5 min until golden brown. Add to a large bowl.
Add EVOO to a pan and add in onion, celery and carrot. Add in garlic. Cook until onion is translucent.
Whisk 3 eggs together with heavy cream and stock. Pour over croissants. Finely chop all the herbs and add herbs and sauteed veggies to the bowl. Grate cheese and add as well. Season with salt and pepper. Mix to combine and add more veggie stock/heavy cream if needed. The croissants should be fully absorbed.
Coat cocotte with butter and add stuffing. Fill up until it’s about ¾ full. Top and bake at 350 for about 30 min.
Remove casings from breakfast sausage and add to a pan with butter and sage. Break down sausage and cook until browned, about 4-5 min. Remove from pan.
In the same pan, crack an egg and season with salt / pepper and add gruyere if you’d like.
When stuffing has cooked for 30 min, remove from oven and add breakfast sausage to the top. Bake again for another 5-7 min. Remove and top with sage butter egg. Enjoy!