Heat milk and cream in a saucepan over medium heat until simmering, about 5 minutes. Slowly whip in Parmesan and Romano cheeses and remove from heat. Whisk egg yolks together in a heat-proof bowl and slowly add about 1/4 cup of the hot sauce to temper eggs. Whisk egg mixture into the saucepan slowly. Season with salt and pepper. Allow Alfredo sauce to cool and refrigerate until needed.
Combine salad dressing, rosemary, and lemon juice in a large bowl. Add steak and stir to coat. Marinate in the refrigerator for 4 hours.
When ready to prepare the meal, preheat an outdoor grill for medium heat and lightly oil the grate.
Fill a large pot with lightly salted water and bring to a rolling boil. Cook fettuccine at a boil until tender yet firm to the bite, about 8 minutes.
Heat 2 cups refrigerated Alfredo sauce in a saucepan over medium heat. Add spinach and 2 tablespoons Gorgonzola cheese.
Remove steak from marinade and cook on the preheated grill to desired doneness, 5 to 10 minutes.
Pour hot Alfredo sauce into a large serving bowl. Add cooked pasta and mix to combine. Sprinkle remaining Gorgonzola cheese on top. Add grilled steak and drizzle the meat with balsamic glaze. Garnish with parsley.
