¼cupgrated Parmesan cheeseI used Parmisano-Reggiano
3Tablespoonsextra-virgin olive oil
½teaspoonfine sea salt
½teaspoonground black pepper
¼teaspooncayenne pepperuse more or less based on your family's tastes
Turn on oven and set to the BROIL setting. Line a baking sheet with aluminum foil and place the bell peppers on top.
Place under the broiler until the skin starts to blacken and bubble. Turn the peppers a 1/4 turn with tongs on each side until the peppers are completely charred. Remove from oven and place in a large bowl.
Cover the bowl with plastic wrap and set aside to allow peppers to sweat and cool down enough to handle.
Remove the skins and seeds from the peppers and discard. I used the plastic wrap that had been used to cover the bowl.
Place the peppers, toasted walnuts, Parmesan cheese, olive oil, salt, cayenne and black pepper into the bowl of a food processor.
Puree until smooth, scraping down the sides as needed.
Adjust seasonings as needed and serve.
To toast walnuts in the oven: Place in a 375 degree oven spread out on a baking sheet and bake for 10 to 15 minutes, until they just start to brown and become fragrant.
To toast walnuts on the stove: Heat a large frying pan over medium-high heat. Place a single layer of walnuts in the hot, dry pan and cook stirring frequently until they start to brown and become fragrant, about 5 minutes.
Substitute pine nuts for the walnuts if desired.
Store unused sauce in an air tight container in the refrigerator for up to 5 days.
This recipe makes about 1 cup of sauce, 16 Tablespoons.