Bring a large pot of salted water to a vigorous boil and cook the penne until just al dente, about 10 minutes. Drain and set aside.
Meanwhile, pat the shrimp dry and heat olive oil in a deep skillet over medium-high heat. Add the shrimp, season with salt and pepper, and sear until pink and slightly caramelized, about 2-3 minutes per side. Remove and set aside.
Add butter to the same skillet, letting it melt over medium heat. Once melted, add the minced garlic and sauté until fragrant, about 30 seconds, until it turns golden and releases a nutty aroma.
Pour in the heavy cream and gently simmer, stirring constantly, until it thickens slightly and becomes glossy, about 2-3 minutes. The cream should shimmer but not boil vigorously.
Add the grated Parmesan cheese gradually to the sauce, stirring until melted and smooth. The sauce should coat the back of a spoon and have a velvety texture.
Return the cooked shrimp to the skillet, tossing gently to coat in the sauce. Finish with a squeeze of fresh lemon juice for brightness, then season with additional salt and pepper as needed.
Add the cooked penne to the skillet, tossing to coat evenly in the creamy sauce. If the sauce is too thick, add a splash of reserved pasta water to loosen it up.
Allow the pasta to rest off the heat for 1-2 minutes, letting the flavors meld and the sauce to thicken slightly. Serve immediately, garnished with extra Parmesan and fresh herbs if desired.