After removing the Brussels sprouts from the stalk and washing them, cut them in quarters. Set aside.
Cut the cooked chestnuts in quarters. I cheated and bought the pre-cooked ones from Trader Joe's. Set aside.
Cook some bacon until it's about 90% done and then slice them up into small pieces. Set aside.
Heat up some olive oil in a large pan and cook the bacon until it's 100% done. This will allow some of the bacon fat to mix in with the olive oil.
Add the Brussels sprouts and cook on medium-high heat for about 12-15 minutes. I added a little water to help it cook a little faster. Add the chestnuts when it's about half way or 3/4 of the way cooked. Add salt and pepper to taste. Remember that the bacon is salty so be careful not to add too much more salt. Once the water evaporates the sprouts can be cooked until you see the nice brown caramelization.
I had intended to add shallots but forgot to buy them, next time I will.