Preheat oven to 300 degrees Fahrenheit.

Peel and quarter the onion and remove the excess leaves from cauliflower. Then place the onion and cauliflower onto a baking tray and coat the pieces with the Sriracha Sauce. Put the tray in the preheated oven for 20 minutes, or until softened.

In the meantime, add butter to a pan over medium heat.

Add the chopped potatoes to the pan and stir for 2 minutes.

Add the salt, pepper, and broth and allow the mix to simmer on low heat for 20 minutes.

Place the cauliflower and onions into a blender (cut up the cauliflower to fit), then add the broth mix from the pan to the blender.

Add the cheese to the blender as well, then blend the ingredients at high speed until smooth.

Add cheese and blend on high speed until smooth

Serve the soup with extra Sriracha on top as a garnish (optional.)