Arrange the red bell peppers, tomatoes, onion, and a head of garlic on a lined baking sheet. Drizzle with olive oil and season with salt.
Roast at 450°F for about 30 minutes, until softened and lightly charred.
Let cool slightly, then remove the skins from the peppers and tomatoes.
Add the roasted peppers, tomatoes, onion, and roasted garlic cloves (squeezed out of the head) to a blender. Add in the white beans, paprika, red pepper flakes, and 3–4 cups broth (use less for a thicker soup, more for a thinner one). Blend until smooth.
Pour the blended mixture into a large pot with the tomato paste, sherry vinegar, a pinch more salt, and some black pepper if you’d like. Simmer gently until warmed through and flavours have melded.
Ladle into bowls and top with torn basil, red pepper flakes, and a drizzle of olive oil. Serve with crackers for dipping—I love Firehook’s Rosemary Sea Salt Crackers.