Melt butter in large soup pot over medium-high heat.

Place diced onions,chopped carrots and chopped broccoli into the pot. Stir. Allow the vegetables to cook for about 4-5 minutes, stirring occasionally.

Reduce heat to medium. Pour in the chicken broth, milk and heavy cream. Stir.

Add all-purpose flour, sea salt, black pepper, and red pepper flakes to the pot while stirring.

Continue to cook and stir the soup for about 10 minutes as it thickens.

Sprinkle in the shredded cheddar cheese and mix until fully incorporated into the soup. Serve.