What makes this herb-crusted roast pork so tasty? The combination of the sour mustard and the sweet thyme leaves. And the incomparable flavor of the balsamic vinegar in the dressing. Amazing.
Rub the pork loin generously with salt and pepper.
Heat about two tablespoonfuls of olive oil in a pan, add the pork, fat side down, sprinkle with the rosemary, and cook until lightly browned. Roll the pork in the hot oil for even browning.
Transfer the pork to a rack set over a baking dish (to catch drippings).
Take the oil in the pan (with the rosemary) and brush all over the browned pork.
Roast in a preheated 375F oven for 20 minutes.
When the pork is almost done, strip the thyme leaves off the stalks and chop the leaves.
Take out the pork out of the oven and place on a cutting board.
Spread the mustard evenly all over the hot meat and press the thyme evenly into the mustard.
Cover the pork loosely with a foil tent and allow to rest.
Cook the asparagus
In a bowl, whisk together the garlic and balsamic vinegar.
Pour in the about 2 to 3 tablespoons of olive oil in a slow thin stream while whisking continuously.
Heat a tablespoonful or so of olive oil in a frying pan.
Add the baby asparagus in a single layer.
Cook, tossing or stirring lightly, to coat each spear with oil (baby asparagus will cook in five minutes or less; larger spears will cook in 10).
Drizzle a few tablespoonfuls of the vinaigrette and cook a few seconds longer.
Assemble the Roast pork loin with mustard and thyme, and baby asparagus
Transfer the asparagus, with the liquids, on one side of the serving platter.
Cut the roast pork into about ¾ inch slices.
Arrange the pork slices beside the asparagus.
Drizzle all the remaining vinaigrette all over the pork.