01 -
Melt the butter in a large pot over medium-high heat. Add the chopped onions and sauté, stirring frequently, for 4 to 5 minutes until they are soft and translucent but not browned.
02 -
Add the minced garlic followed by the all-purpose flour to the pot. Stir continuously for about one minute, allowing the flour to coat the onions without burning, forming a roux that will thicken the soup.
03 -
Slowly whisk in the milk, ensuring a smooth mixture, then add the chicken broth. Stir in the chopped broccoli florets evenly. Increase the heat and bring the mixture to a gentle simmer.
04 -
Reduce heat to maintain a gentle simmer. Cook, stirring occasionally, for 6 to 8 minutes until the broccoli is tender and the soup has thickened.
05 -
Remove the pot from heat. Gradually stir in the heavy cream, followed by the cheddar and Parmesan cheeses in small batches, stirring thoroughly after each addition until fully melted and smooth.
06 -
Adjust seasoning by adding salt and freshly ground black pepper to taste. Serve the soup hot, optionally topped with extra shredded cheddar cheese for added richness.