Combine all ingredients in a food processor, pulsing a few times, to maintain a grainy texture. If pesto is too thick, add some oil.
- Spread pesto on the inside of each bun half.
- Layer 2 cheese slices on 4 bun halves.
- Add mortadella.
- Top with a piece of roasted pepper and season with ground pepper to taste.
- Top with other bun half.
- Wrap in wax paper. Keeps in fridge a few hours.
- Bring to room temperature before serving.
- Since mortadella is already very salty, adjust salt in pesto.
- Choose peppers canned without vinegar. Rinse and pat dry before adding them to your sandwich. You can also add a few
- Parmesan shavings and spinach leaves to top your sandwich.
- Pesto keeps 3 days in the fridge, covered in a thin layer of olive oil.
- Double the pesto recipe and use in pasta.