Using a sharp knife, cut shrimp in half lengthwise. Place in a large bowl, cover, and refrigerate.
In a medium stockpot, heat olive oil and butter together over medium heat. Add onion, carrot, and celery. Cook, stirring occasionally, until vegetables are just tender, approximately 5 minutes. Add wine, and simmer until volume is reduced by half, approximately 6 minutes. Reduce heat to medium-low. Stir in tomato paste until well combined. Stir in flour, and cook, stirring occasionally, until thickened, approximately 5 minutes. Stir in seafood stock until combined. Add thyme and bay leaf. Bring to a boil over medium-high heat, stirring occasionally. Reduce heat until mixture comes to a simmer, and cook for 40 to 45 minutes.
Using a fine-mesh sieve, strain stock into a large, heatproof bowl, discarding solids. Return strained soup to pot. Add salt, pepper, and shrimp. Bring to a simmer and cook just until shrimp turn opaque and pink, 2 to 3 minutes. Stir in cream until combined.
Divide crabmeat evenly among individual servings of soup. Top with Butter-Herb Croutons. Garnish with fresh thyme, if desired. Serve immediately.
Notes
Make-Ahead Tip: Soup can be prepared a day in advance, strained, placed in an airtight container, and refrigerated. Gently reheat soup in a stockpot on stovetop before seasoning and adding shrimp or cream.
Recipe by TeaTime Magazine at https://teatimemagazine.com/seafood-bisque/