Add tomato paste, harissa or red pepper flakes and cook until deepened in color. Stir in crushed tomatoes, chicken broth, bouillon, and lemon juice. Bring to a simmer.
1.5 tablespoon harrisa or ½ teaspoon red pepper flakes, 2 tablespoon tomato paste, 3.5 cups chicken broth, 2 teaspoon chicken bouillon, Juice of 1 lemon