Brussels Sprouts with Onions and Pancetta

Ingredients:
10 oz of Brussels Sprouts
4 oz of Pancetta, chopped into small dice
1 Tbsp of Olive Oil
1 Small Red or Yellow Onion, thinly sliced
1 Tbsp of Unsalted Butter
1 Tbsp of Fresh Chopped Parsley
Salt and Pepper, to taste