Preheat the oven to 356°F.
Place the leg of lamb in a large baking pan and carefully make 5-6 incisions randomly, to the surface of lamb.
Fill the incisions with salt, mint, pepper, the cloves of garlic and the rosemary sprigs.
Toss the remaining rosemary and garlic in the pan.
Rub the lamb with olive oil and season with salt and pepper.
Pour the broth in the pan along with enough water to cover the bottom of the pan by ¼-inch in height.
Cover the pan with aluminum foil, folding the edges to secure that the steam circulates to cook the meat instead of escaping the pan.
Bake in the preheated oven for 3 hours.
Remove from the oven and make the gravy.
Remove the lamb carefully from the pan and set aside covered to keep warm. Remove any sprigs of rosemary and garlic from the pan.
Place the roasting pan on the stovetop. Turn the heat on to medium-high and add the almond flour. Whisk to combine.
Pour in broth in a stream, while whisking. Cook for a few minutes until it’s reduced to a velvety, thick gravy.
Serve the lamb with a generous dose of the gravy.