Place the broiler on high.
Arrange 12 hot peppers and all of the sweet peppers on a baking sheet and char evenly all over – keep oven door slightly ajar to allow steam to escape. Place charred peppers in a bowl and cover with plastic wrap. Let cool, then peel, seed and slice.
Turn off broiler and preheat oven on to 325°F.
Butterfly the pork shoulder open and flatten it out.
Place lemon juice and about 1/4 cup EVOO in a food processor. Coarsely chop remaining red chili pepper and add to processor bowl with garlic, bay, rosemary, thyme and parsley. Pulse-chop into a thick, pesto-like sauce.