Italian Tomato Stew with Fennel, Mushrooms & Spinach

I made this today for the first time, and I went strictly by the recipe.  I didn't find it too spicy hot.  You could use mild sausage to tame it down, if you wanted.

1 lb. hot sausage

1/2 red onion chopped small

1 scallion chopped finely

stalks and leaves from 1 fennel bulb, stalks sliced thinly and leaves roughly chopped.  Bulb chopped

6 large mushrooms, roughly chopped, about 1 cup pieces

1 large tomato chopped small or 1 can (14 oz)  diced tomatoes

1 can (14 oz) diced fire roasted tomatoes

1 can (14 oz) Italian stewed tomatoes

2 cups water

1 tsp oregano

1 tsp basil

1 tsp kosher salt

4 cups baby spinach leaves add a bit more if not using kale with the spinach

generous amount of finely shredded Pecorino Romano cheese or Parmesan cheese

In the bottom of a large Dutch oven, cook and crumble the sausage.  Add the onions and fennel and cook a few more minutes, just until the onions start to soften.  Add all remaining ingredients EXCEPT the kale and spinach.  Simmer for half an hour.  Taste and adjust seasoning as desired.  Add the greens, stir to combine.  Simmer for just a few minutes until they are slightly softened and wilted.  Top individual servings with plenty of shredded cheese.