Preheat the oven to 425 degrees F. Remove the butter from the fridge so that it starts to soften. 

To prepare for baking, cut small openings on the fleshy side of the leg. Try to make about 10-12, 2 in deep cuts, big enough to fit a slice o garlic, half an anchovy and a small sprig of rosemary. Do this until you run out of garlic but still have half of the anchovies remaining.

In a small bowl cream together the softened butter and the rest of the anchovies. I use my hands for this part: smear everything all over the leg. Now sprinkle pepper all over the leg and place in a roasting pan. Pour the wine or chicken stock into the bottom of the pan.

Pour the lemon juice all over the meat and top with any leftover rosemary sprigs.

Set it on the center rack to roast for 15 minutes, then lower the temperature to 350 degrees F and leave for another hour. You can baste the meat 4 or 5 times during this hour. 

You can let it cook a little extra if you want your meat more well done but I take mine out at the hour mark and let it rest for 15 minutes, reserving the liquid. The residual heat will continue to cook the meat even after it's out of the oven.

At this point, you can taste the liquid to see if it needs anything. Add salt or pepper to taste. If you want your gravy to be a little thicker, add to the stove and let it simmer (you can add flour a tsp at a time and whisk for even heartier gravy)

Carve and serve with gravy over the meat.