Start by bringing a large pot of salted water to a boil. Add the fettuccine noodles and cook according to the package instructions until al dente. Once cooked, drain the pasta in a colander and set aside.
In a medium saucepan over medium heat, melt the butter. Once melted, add the minced garlic and sauté for about 1 minute until fragrant, being careful not to let it brown.
Sprinkle the flour over the melted butter and garlic. Whisk constantly for about 1-2 minutes to create a roux, which will help thicken your sauce.
Gradually pour in the heavy cream and milk while whisking continuously. Bring the mixture to a gentle simmer.
Once the sauce has thickened slightly, lower the heat and stir in the grated Parmesan cheese and Romano cheese. Continue whisking until the cheese has melted and the sauce is creamy and smooth.
Add the cooked fettuccine noodles to the sauce and toss to coat the pasta evenly with the Alfredo sauce. If the sauce is too thick, add a splash more of milk to reach your desired consistency.
Serve the Copycat Olive Garden Alfredo immediately in bowls or on plates. Garnish with freshly chopped parsley for a burst of color and freshness.