1. In a large (5.5 quart or larger) heavy-bottomed pot, over medium heat, add olive oil. Add onion, carrot, celery, and salt/pepper to taste (about 2 teaspoons salt and 1 teaspoon pepper). Cook until vegetables are soft and onion begins to turn golden, about 7–9 minutes.

2. Add garlic, Italian seasoning, cumin, thyme, and red pepper flakes. Cook, stirring constantly, for 1 minute.

3. Add rinsed split peas, bay leaves, and vegetable stock. Stir, bring to a boil, then reduce heat to low and simmer uncovered for 60–90 minutes, stirring occasionally.

4. Cook until split peas have broken down and soup is thickened to desired consistency. Stir more frequently as the soup thickens. Add more stock if it gets too thick.

5. Remove and discard bay leaves. Blend 2 cups of soup until smooth and return to the pot. Stir to combine.

6. If using lemon, zest and juice it to get 1 teaspoon zest and 2 tablespoons juice. Add to the soup. Taste and adjust seasoning with additional salt and pepper if needed.

7. Ladle soup into bowls. Serve with hearty buttered bread, a sprinkle of pepper, and fresh parsley or thyme. Add Parmesan cheese to individual bowls if desired.