A rich and creamy seafood bisque loaded with crab and shrimp, gently seasoned with Old Bay and enriched with butter, cream, and tomato paste. Long, slow simmering develops deep flavor—finish with a sprinkle of fresh parsley for an elegant bowlful.
Melt the butter over medium-high heat in a saucepan. Add the chopped celery and green onions and cook, stirring occasionally, until they soften and become translucent, about 4–5 minutes.
Make Roux
Sprinkle the flour over the softened vegetables and stir continuously for about 1 minute to cook out the raw flour flavor and form a light roux.
Add Dairy and Season
Warm the milk until just hot but not boiling. Slowly pour the warm milk into the pan while whisking to eliminate lumps. Stir in the heavy cream and tomato paste until smooth, then whisk in Old Bay seasoning, salt, and pepper to taste.
Simmer and Thicken
Reduce the heat to low and let the bisque simmer gently. Stir occasionally and allow it to thicken and develop flavor; simmering may take up to 1–2 hours depending on desired intensity.
Finish
When the soup has thickened, add the shrimp and crab meat and warm through until heated, about 3–5 minutes. Taste and adjust seasoning as needed.
Ladle the bisque into bowls, garnish with chopped fresh parsley if desired, and serve immediately.