Cut the cauliflower into small florets and wash them thoroughly.

Set aside a few florets to garnish the soup later.

Finely slice the onion or leek whites and mince the garlic clove.

Melt the butter in a Dutch oven or large pot, then sauté the onion or leek whites with the garlic, sweating them gently without letting them brown.

Add the cauliflower florets and pour in enough water to just cover them.

Crumble the two chicken bouillon cubes over the vegetables.

Cook uncovered over medium heat for about 30 minutes, or until the cauliflower is very tender. Check doneness with the tip of a knife and add a little water if needed.

Once the cauliflower is cooked, add the milk and bring the soup to a gentle simmer.

Blend the soup until very smooth using an immersion blender. For an even silkier texture, you can strain it through a fine sieve.

Return the soup to the heat, stir in the cream, and adjust the consistency if needed. Season with salt and pepper. The Crème Dubarry should be rich and creamy.

If using the egg yolk for thickening, whisk it into the cream before adding it to the soup.

Let the soup simmer gently for a few minutes, then remove from heat.

Serve in bowls and garnish with a few cauliflower florets for a bit of crunch. You can also blanch the florets for 10 minutes in boiling water, then refresh them in ice water to keep them slightly crisp.

This creamy cauliflower soup is smooth, comforting, and sure to become one of your favorite cauliflower-based recipes.