Bring a large pot of water to a boil. Add a small handful of salt and add spaghetti.
Boil spaghetti, stirring occasionally until al dente, about 5 to 7 minutes. Drain and toss with olive oil and set aside.
Place pancetta into a large skillet and place over medium heat. Sauté until pancetta becomes crispy, about 3 minutes.
Remove pancetta onto paper towels with a slotted spoon and set aside.
Drain all but 1 tablespoon of the grease from the skillet and add 1 tablespoon of butter.
Raise the heat to medium-high and add shredded Brussels sprouts. Sauté for 2 to 3 minutes or until the edges of the Brussels sprouts become golden brown and crispy. Season with salt and pepper. Remove from the skillet and set aside.
Add remaining butter into the skillet and add shallots and garlic. Lower heat back down to medium and sauté for 2 to 3 minutes. Season with salt and pepper.
Add cream and simmer until reduced by ½ and cream has thickened.
Stir the Parmesan into the cream mixture and stir until smooth. Add spaghetti and pancetta to the skillet and toss together until evenly coated. Season with salt and pepper.
Top spaghetti with the crispy Brussels sprouts, more Parmesan and serve.