1Melt the butter in a large pot over medium-high heat. Stir in the celery, scallions, potatoes and corn.
3Add the thyme, bay leaves, 1/2 teaspoon salt and a few grinds of pepper and cook, stirring, 3 minutes. Stir in the flour until incorporated, about 2 minutes.
5Stir in the milk, then cover and bring to a boil. Uncover, reduce the heat to medium low and gently simmer until the vegetables are tender, about 6 minutes. Remove from the heat. Discard the thyme sprigs and bay leaves.
7Transfer one-third of the mixture to a blender and puree until smooth, then return to the pot. Return to a simmer over medium-high heat.
9Stir in the shrimp and cook until opaque, about 4 minutes. Season with salt.
11Sprinkle with paprika.