Rub venison with mustard. Combine salt and peppercorns and evenly coat venison. Grill or broil until just barely browned on the outside, but still rare on the inside. Allow to cool. Slice bread into 1/4-inch thick slices. Combine oil and garlic and brush over sliced bread. Toast in a 350 degree oven until lightly browned. Cool.

Slice cooled venison a thinly as possible. Combine mayonnaise and herbs. Place a dollop of mayonnaise on each toast. Top with sliced venison and garnish with a parsley sprig.