Mallmann's Mustard Lamb

Lusty flavors and a a deep char give this a great taste on the BBQ; quick and easy. Adapted from Francis Mallmann's "Seven Fires: Grilling the Argentine Way". Serves 2.

 16 oz  450 g     Lamb Leg
                  Salt
                  Pepper
1/4 cup  60 ml    Dijon Mustard
1/4 cup  handful  Fresh Oregano, fresh (omit if you only have dried)
  1       1       Lemon
                  Oil

Cut one or two inch-thick slices from the Lamb, across the grain; if you end up cutting more small pieces, that's fine.
Remove any obvious gristle and excess fat.
Cover with cling film and pound flat to an even 1/2 inch thickness.
Season both sides generously with Salt and Pepper.
Brush both sides evenly with Mustard.
Press chopped Oregano onto one side only, and press a thin Lemon slice on each piece.

On the BBQ, get a cast iron griddle or pan ripping hot.
Drizzle with oil and when smoking, slap on the Lamb, Lemon/Oregano-side down.
It will smoke a lot.

Let cook undisturbed until the Lemon and Oregano are charred (you'll have to peek carefully).
Flip and finish cooking to your desired internal temperature, about 135F is good: it should retain a bit of pink.
Serve with a rich Malbec, and vegetables grilled on the griddle.