For the croutons:

1. There are two ways you can prepare the croutons. On top of the stove or in the oven. Here are instructions for both methods.

Skillet Instructions:

1. In a large pan, melt the butter and olive oil together over medium heat. When the foaming subsides, add the bread cubes and toss frequently until all pieces are coated. Continue stirring around until all pieces are golden brown and crisp, about 5-10 minutes. Toss the hot croutons with the seasonings until evenly distributed. Serve with soup.

Oven Instructions:

1. Pre-heat your oven to 400 degrees. In a bowl, melt the butter and olive oil in the microwave, covered, for about 30 seconds. Toss the bread into the butter and oil mixture and make sure each piece is evenly coated. Place buttered bread cubes on a baking sheet and bake until all pieces are golden brown, about 10 minutes. Please keep an eye on it! When they’re toasted to your liking, toss them with the seasonings and serve.

For the soup:

1. In a large pot or dutch-oven, melt the butter over medium-high heat. Add the chopped broccoli, onion, garlic, mustard, red pepper flakes, cayenne and 1 teaspoon of regular salt. Cook the mixture down until fragrant, while stirring frequently for about 5 to 6 minutes. Reduce the heat to medium.
2. Stir the baking soda in 1 cup of water, and add to the broccoli mixture (the baking soda breaks down the fibers of the broccoli to make it softer to puree later). Bring to a simmer, cover and cook until very soft, about 20 minutes — stirring only once.
3. Add 2 cups of chicken or vegetable broth, plus 2 more cups of water. Increase the heat to medium-high. When it starts to simmer, add the spinach and cook until wilted for about 1 minute.
4. Transfer half of the soup to either a food processor or blender. Add half of both cheeses (3oz of the cheddar, 1/2 cup of the parm) and blend until you’ve reached your desired consistency and all visible chunks of cheese are no longer visible. Feel absolutely free to leave some whole pieces of broccoli in your soup if you choose to. Pour the blended soup into a separate bowl. Repeat this process with the remaining half of the soup and cheeses and bring back to the pot or dutch-oven. Bring to a simmer over medium heat until heated through. Adjust texture by adding more water if desired, a little at a time. I ended up adding just 1/4 cup more of water but this is where you are in total control of the outcome. Adjust it to your own personal needs. Taste and season with sea salt and freshly ground black pepper.
5. Serve and top with croutons, bacon, and more grated parmigiano-reggiano if you’d like.
6. Enjoy!