Remove excess fat from the flank steak and butterfly it along the grain. You want your matambre slices to be against the grain for tenderness and chewability.
If one side of the meat is more fatty, put that side down so it will be on the outside of your roll and browned during cooking.
Sprinkle the meat with the black pepper and paprika. No salt because of the cheese.
Make sure your meat is set up so you will be rolling with the grain.
In a bowl, mix the milk, bread crumbs and 2 raw eggs,
Chop the parsley by hand or in a food processor and then add it to the paste bowl.
Finally, process the cheese and garlic in the food processor and then add it to the paste bowl. I like to use block cheese and the food processor is an efficient grater. You can also use pre-grated cheese.
Spread the paste on the top of the meat.
Add the slices of pepper and carrot, and the quarters of egg to the top of the parsley paste. Make sure your rows run along the grain.
Roll the meat along the grain and then follow the YouTube video instructions below for tying a roast.
Preheat your oven to 375F.
In a large pan or dutch oven, add 2-3 Tbsp of oil and brown the meat on your stovetop on all four sides, about three minutes each side.
Cover the pan and put it in the preheated oven. Bake for about 30 minutes.
Let the meat rest at least 10 minutes before cutting it. Alternatively, transfer the meat to a storage container, weighing it down with a plate if possible, and refrigerate it. You can serve it cold or reheat it the next day.