serving size: serves 6 ingredients: 2 tablespoons stalks and fronds removed, thinly sliced i onion, chopped 3 large shallots, chopped 2 teaspoons kosher salt, plus more to taste 3 large garlic cloves, minced 3/4 teaspoon dried crushed red pepper flakes, plus more to taste 1/4 cup tomato paste 1 (28