Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente, usually about 10 to 12 minutes. Drain well and set aside, reserving a little pasta water for later if needed.
While the pasta is cooking, heat a skillet over medium heat. Add the turkey bacon slices and cook until they’re crispy and browned, about 4 to 5 minutes per side. Remove from the skillet, let cool slightly, then crumble into bite-sized pieces.
In a mixing bowl, combine the shredded cheddar cheese, sour cream, ranch dressing, garlic powder, onion powder, salt, and pepper. Stir well until the mixture is creamy and smooth.
Return the drained penne to the pot or a large mixing bowl. Pour the cheese and ranch sauce over the pasta and toss to coat evenly. If the sauce feels too thick, add a splash of the reserved pasta water to loosen it up.
Fold in the crumbled turkey bacon gently. Transfer the pasta to serving plates or bowls and sprinkle the chopped green onions on top for a fresh pop of color and flavor.