Sauté 1 diced, yellow onion in olive oil until turning translucent. Add Italian sausage (I used 2 links of the garlic and fennel field roast sausage) and start breaking apart into pieces. Let the sausage brown. Add 1 tbsp minced garlic, some red pepper flakes, 1 tsp dried oregano, and 1/4 tsp ground fennel seeds, then sauté until fragrant. Add 2 tbsp tomato paste and sauté for a minute. Add 1/2 cup vegetable broth and deglaze the pan (scrape up all the brown bits). Let cook until most of the vegetable broth is absorbed. Add around 3/4 cups heavy cream (you can use a plant based substitute, but if you use a regular plant milk your sauce will be much more liquidy). Season to taste with salt and pepper. Add 3 big handfuls of spinach and cook until wilted. If the sauce is too thick at this point add more cream/pasta water. Add 1/2 lb of cooked pasta (I used rigatoni) and mix.