Escarole and Cannellini Bean Soup in Parmesan Broth

INGREDIENTS

3 tbsp

olive oil

1/2

small onion, finely diced

kosher salt

to 4 cloves garlic, minced

1 lb

escarole, chopped

8 cups

vegetable broth

to 2 ounce rind of Parmesan

2 15 ounce cans

cannellini beans, drained and rinsed

large egg

freshly ground black pepper

Parmesan for grating

lemon wedges for serving