2tablespoonsdried Herbes de Provence(recipe note #1)
½teaspoonfreshly ground black pepper
Place an oven safe rack inside a rimmed baking sheet lined with foil (for easy cleanup).
If lamb roast is tied, untie and unroll. Trim away thick areas of fat and tendon from the top and bottom of the roast, leaving a thin layer of fat on top.
Whisk together all Dijon Herb Paste ingredients in a medium bowl until they emulsify into a uniform paste.
Spread ⅓ of herb paste all over underside of roast. Roll roast back up into its original shape and snugly tie in the center and at both ends with three lengths of kitchen twine. Rub outside all over with remaining herb paste. Transfer roast, seam side down, to rack on prepared baking sheet and let stand at room temperature while the oven preheats.
Preheat oven to 425°F.
Roast lamb in hot oven for 15 minutes. Reduce heat to 350˚F and cook until an instant read thermometer inserted into the center registers 130˚F to 135˚F (for medium rare - the temperature will rise as the roast rests before slicing), 1 to 1 ¼ hours. Transfer roast to cutting board; let stand 15-30 minutes before slicing.
Snip twine with kitchen shears; remove and discard. Slice roast thinly (about ¼-inch) and arrange on platter. Serve.
If you love the combination of rosemary and lamb, use 1 tablespoon of Herbes de Provence and 1 tablespoon of minced fresh rosemary. And / or to add brightness to herb paste, stir in 1 teaspoon of fresh lemon zest or more.