Place a wire rack on a baking sheet.

Take the pork butt and cut it (going with the grain) from top to bottom, so you have 2 equal size roasts. Take a sharp paring knife or blade and slice a few slits in the fat cap. Lay each roast on its side, take the knife and cut a few slits in the pork butt on both sides, every 1 inch or so. We do this so we can stuff the herb mixture into the pork!

Sprinkle the 2 roasts all over with the kosher salt.

In a bowl, combine the rosemary, thyme, sage, lemon zest, fennel seed, garlic, salt and pepper. Stir to combine. Add the olive oil and stir to form a spreadable paste.

Take the paste and rub it all over the pork and into the slits that you sliced. I rub the paste heavily on both sides, into the cuts, on the bottom and a bit on the top. Take kitchen twine and tie both pork butt roasts into a more compact cylinder (as much as you can). Place the roasts on the wire rack on the baking sheet. Do not cover. Refrigerate overnight, or for at least 8 hours.

Preheat the oven to 325 degrees F. Transfer the pork to a baking dish or higher rimmed baking sheet, setting them a few inches apart. Cover the dish with foil.

Roast the pork for 2.5 hours, or until the internal temperature reaches 180 degrees F.

Remove the pork from the oven. Increase the heat in the oven to 500 degrees F. Transfer the pork to another clean baking sheet and gently cut the twine off the pork. Once the oven reaches 500 degrees F, place the sheet with the pork (uncovered) in the oven and roast for 20 to 30 minutes, or until the inside reaches 190 degrees F. This makes the outside SO super crispy! Remove the pork and let it sit for 30 minutes before slicing.

Slice the pork into super thin slices - almost think of shaving it with the knife. And time to serve!

To assemble the sandwiches, spread a baguette with the garlic herb mayo. Top with the greens. Add on the sliced porchetta. Top it with the bun and serve!

Note: you can do the same with pork belly and I use the same method and temperatures. I use 3 to 4 pounds of pork belly - either a slab or a few thin pieces. Slice the slits into the pork belly, spread the paste on, roll them up and tie with twine. Then follow the same instructions - fridge time out, slow roast, high temp crisp up. Let rest and slice!