Make a few cuts in the meat using the point of a sharp knife and stuff some garlic and parsley stems into each cut.
8 cloves garlic, 20 stem parsley
Rub the lemon juice and melted butter into the meat and season generously with salt and pepper.
1 large lemon, salt, ground black pepper
Sprinkle the flour over the surface of the meat.
3 tbsp flour
Roast in a preheated 350F (180C) oven for about 30 minutes per pound (1 hour per kilogram), or until it reaches an internal temperature of 135F (57C) for medium-rare to 160 (70C) for well-done.
Remove from the pan and allow the roast to cool for 15 minutes before slicing and arranging the meat on a serving platter.
Meanwhile, pour off and discard the fat from the roasting pan and add the water, stirring to scrape up all the baked on "brown bits" in the bottom of the pan. In a small saucepan melt the butter over moderate heat and add the flour, stirring constantly until it turns light brown.
1 cup water, 2 tbsp butter, 2 tbsp flour
Add the flour mixture to the water in the roasting pan, stirring it over low heat until the gravy has thickened.
Adjust the seasoning with salt and pepper, pour into a gravy boat, and serve with the meat.
Serves 6 to 8, or more depending on the size of the roast.
Notes
One word - Gorgeous. We had this with friends yesterday and it vanished. Plates were literally licked clean.