If your red peppers aren’t already roasted, then do it now. Just place them on a rimmed baking sheet, into a 425 F oven, and turn occasionally. They’re ready when they’re blackened and collapsed, about 20 to 25 minutes. Remove them from oven and immediately place in a paper bag. This will steam the skin off as they cool. Place in the fridge and once cool, remove from bag, peel off skin and remove seeds.
Now toast the almonds. Preheat a large, heavy bottomed pan over medium low heat. Spread the almonds out in a single layer and toast frequently until fragrant and honey brown, 5 to 7 minutes. Transfer almonds to a food processor. Now we’ll prepare the rest of the sauce.
In the same pan over medium high heat, saute onions in olive oil for 5 to 7 minutes with a pinch of salt, until lightly browned. Add garlic, several dashes fresh black pepper, dried marjoram and salt, and saute for 30 seconds more, then turn off the heat.
Now pulse the almonds in the food processor until they’re a finely ground powder. Add the roasted red peppers, the onion mixture and the red wine vinegar and agave nectar. Puree until fairly smooth. Taste for salt, and set aside until ready to use.