*Balsamic glaze can be made by VERY slowly simmering about 1 cup balsamic vinegar until it is so reduced, it's got a syrupy consistency. Upfront I'll tell you it's a PAIN to make, but fortunately, you can buy it pre-made in a well-stocked supermarket or gourmet store.
Trim fat from sirloin steak. Cut steak into strips about 1-inch wide and 3-inches long. Place steak in a large zipper plastic bag.
Mix marinade ingredients and pour over steak in bag. Seal bag and "mush" the marinade and steak together. Place in refrigerator for 1-3 hours.
After steak has marinated, preheat your broiler or outside grill on high. Grill steak to desired doneness. Remove to a plate and cover to keep warm. I do this in a very low--200 degrees F--oven.
Cook fettucine as per package directions. When done, drain.
Meanwhile, prepare alfredo sauce by heating the milk and cream in a medium heavy-bottomed saucepan. Mix in the cheeses. DO NOT LET THIS BOIL. Whisk egg yolks well in a separate bowl. Pour about 1 cup of the cream/cheese mixture into the egg yolks, whisking while pouring. This is called "tempering" so the eggs don't form a clump when adding it to the sauce. Pour the tempered egg/sauce mixture back in the saucepan while whisking. Continue to whisk over medium-low heat until sauce begins to thicken. This will be anywhere from 3-5 minutes. Add the spinach and sun-dried tomatoes. Stir well, cover and remove from heat.
In a large bowl, combine the hot cooked fettucine with the sauce and toss well.
Plate and top each plate with 1/4 of the steak strips. Drizzle with balsamic glaze if using. Put crumbled gorgonzola on top of steak.