Preheat oven to 325ºF. Place an ovenproof skillet over medium heat with 1 turn of the pan of EVOO, about 1 tablespoon. Add the bacon to the skillet and cook until golden brown and crispy, about 10 minutes. Remove the bacon from the pan to a paper towel-lined plate and let cool (reserve the skillet with the drippings – you'll use it again in a bit).
In a large flat dish, combine 1 cup of flour (eyeball it) with the paprika and set aside.
In a food processor, grind the toast into crumbs, then add in the melted butter and parsley. Pulse to combine.
Season the beef steaks with salt and pepper, and top each with a little bit of the bacon, chopped egg, bread crumbs and chopped watercress. Roll the beef up into a log and secure with some kitchen string or toothpicks. Season the outside of the rolls with salt and pepper and toss them in the seasoned flour to coat.
Return the skillet with the bacon drippings over medium-high heat. Once hot, add the beef roll-ups to the pan (work in batches if your pan can't hold them all at once) and sear them until golden brown all over, about 5 minutes per side.
Add the wine and beef stock to the pan. Bring the liquids up to a bubble and cover. Transfer the pan to the oven and cook until the meat is tender, about 45 minutes. When the meat is finished cooking, transfer rollups to a platter and cover with foil to keep warm.
Place a medium-size saucepan over medium heat with the remaining 3 tablespoons butter. Cook the shallots until tender, about 5 minutes. Add the remaining 3 tablespoons flour to the pan and cook for about a minute.
Slowly ladle the juices from the pan the beef was cooked in into the flour-butter mixture, whisking to incorporate. Bring up to a bubble and simmer until the gravy has thickened, 2-3 minutes. Remove the pan from the heat and stir in the Worcestershire, mustard and chopped cornichons or pickles. Season the gravy with salt and pepper.
Plate two rouladen per person with a hearty ladle of gravy on top. Serve with boiled quartered potatoes with chives and warm buttered radishes alongside.