This recipe is inspired from an episode of Good Eats with Alton Brown. Its a shame that the hatch chile season is so short, but the chiles are amazing when you can find them fresh. The combination of cured pork with pork tenderloin and roasted New Mexico Hatch green chiles makes for a great meal to share. It's easy to make and your friends will be impressed by the presentation. —The Gaussian Kitchen
Place all ingredients in a mortar and grind together with the pestle until the thyme and pepper have broken down and released their flavor into the mustard.
Prep: ~40min | Cook: ~25min | Pre-Heat Oven: 400
Remove the silver skin from the pork tenderloin, and cut in half length wise.
Lay the prosciutto out in an overlapping layer on a sheet of cling wrap. Use enough prosciutto to cover the length of the pork tenderloin. Salt and pepper the prosciutto to taste. Cover with parchment paper and roll out with a rolling pin. This will keep the prosciutto together during rolling.
Lightly press and drain the roasted hatch chiles to remove some of the water.
Place the pork tenderloin halves in the middle of the prosciutto and put the hatch chiles in between the pork halves.
Tightly roll the prosciutto around the stuffed pork tenderloin. You can use the cling wrap to roll and keep the rolled product tight while you prepare the puff pastry.
On a floured surface roll out the sheet of puff pastry large enough to roll the pork in.
Spread the mustard on the puff pastry.
Place the pork in the center of the puff pastry and roll. Pinch the pastry to seal the ends and the seam.
Paint the egg wash on the puff pastry.
Place the pork wellington on a pan lined with parchment paper. Cook in the preheated oven for about 25 minutes, until the internal temperature of the pork reaches 140-145 degrees.
Remove from the oven and let rest for 10 minutes.
Slice 1.5 inch thick portions using a long serrated knife using as few strokes as possible and plate 1-2 slices per person.