Cook pasta according to package directions (al dente). While pasta is cooking prepare the Brussels sprouts (see step 2 below). Drain pasta and return pasta to pot, reserving about 1 cup of pasta water.
Trim ends off Brussels sprouts and cut in half lengthwise. Heat 1 Tbsp olive oil in a large skillet over medium-high heat. Once skillet is very hot place Brussels sprouts cut side down in skillet. Reduce heat to medium and sear until golden brown (about 3-5 minutes). Turn sprouts over and sear other side until golden brown and tender (about 3-5 minutes). Remove Brussels sprouts from pan and set aside.
Return skillet to stovetop and heat remaining 1 Tbsp olive oil on medium . Add garlic and cook for one minute. Add half & half (or cream) and lemon zest. Bring sauce to a boil and reduce to a simmer until sauce thickens ( about 6-8 minutes). Stir in Parmesan cheese and lemon juice.
Pour sauce in pot with cooked pasta. Add seared Brussels sprouts. Heat as necessary until pasta and Brussels sprouts are warm, adding reserved pasta water as necessary for sauce to coat the pasta ( you may not need the full 1 cup reserved water).Add salt and pepper to taste.
Transfer pasta to a bowl and garnish with crumbled bacon, toasted walnuts or extra Parmesan cheese if desired.
* if you're a garlic lover add a few additional cloves