Bring a large pot of salted water to a boil, then add the penne and cook until just al dente, about 10 minutes. Drain and set aside.
Meanwhile, heat a large sauté pan over medium heat. Add a tablespoon of olive oil, then toss in the shrimp. Season with salt and pepper and cook for 2-3 minutes per side until they turn pink and opaque. Remove the shrimp from the pan and set aside.
In the same pan, reduce the heat to medium-low. Add the butter and minced garlic, sautéing until fragrant and just beginning to turn golden, about 30 seconds. The garlic should smell pungent and aromatic, filling the air.
Pour in the heavy cream, stirring constantly as it gently bubbles. Let it simmer for 2-3 minutes until slightly thickened, creating a rich, silky base for the sauce.
Add the grated Parmesan cheese gradually, stirring continuously to melt and incorporate it smoothly into the cream, resulting in a glossy, cheesy sauce.
Return the cooked shrimp to the pan, then add the drained penne. Toss everything gently to coat the pasta and shrimp evenly with the creamy sauce. Cook for another 1-2 minutes until heated through and flavors meld.
Finish by squeezing in a teaspoon of fresh lemon juice, stirring to brighten the dish. Taste and adjust seasoning with salt and pepper if needed.
Serve the shrimp Alfredo penne hot, garnished with extra Parmesan or chopped parsley if desired. Enjoy the creamy, savory flavors in every satisfying bite.