Step 1

Heat the olive oil in a large pot over medium heat. Add the onion, carrot, celery, 1/2 teaspoon salt, oregano, black pepper, and red pepper flakes. Cook, stirring occasionally, until the vegetables have just softened, about 7 minutes. Add the garlic; cook, stirring often, about 2 minutes more.

Step 2

Add the broth and undrained tomatoes; stir to release any browned bits from the bottom of the pot. Increase the heat to medium-high and bring to a boil. Add half of the beans to a bowl; mash with a fork and stir into the soup. Add the remaining beans and the pasta to the pot; reduce heat to medium. Simmer, stirring occasionally to prevent sticking, for 10 minutes. Stir in the kale and cook until the pasta is tender, about 5 minutes more. Remove from the heat.

Step 3

Zest the lemon, then cut it in half. Squeeze one lemon half into the soup. Add 1 teaspoon of the ;zest and ;stir to combine. Taste and add more lemon juice or salt as desired. Top servings with Parmesan cheese.