The thickness here will be up to your preference. I like my ragu sauces to be pretty thick, so I add both tablespoons of cornstarch. I would start by just simmering the sauce down for 15 minutes, adding your shredded beef, and seeing what you think of the consistency. If you want it thicker, go ahead and stir in 1 tablespoon of cornstarch slurry and let it cook for 30 seconds – 1 minute. If you want it even thicker, add the second tablespoon of cornstarch slurry. I preferred mine with both tablespoons – I thought that was the perfect consistency!
I didn’t measure exact serving sizes with this recipe, but it was plenty to coat 1 pound of fettuccine pasta.