Slow-Cooker Shrimp & Crab Bisque

Ingredients

• 1 tablespoon olive oil
• 2 tablespoons butter
• 2 leeks (chopped, white and light green parts)
• 4 cloves garlic (minced)
• 1/2 teaspoon red pepper flakes (adjust to taste)
• 2 tablespoons tomato paste
• 1 cup dry sherry or marsala wine
• 4 cups seafood or fish stock
• 1 (15-oz) can diced tomatoes
• 1 teaspoon Old Bay seasoning
• 1 tablespoon sugar
• 1 cup water
• 1/4 cup all-purpose flour
• 2 teaspoons kosher salt
• 1 teaspoon black pepper
• 1 cup half-and-half or heavy cream
• 1 lb peeled and deveined shrimp
• 1 cup jumbo lump crab meat
• Fresh parsley and lemon wedges (for garnish)
• Toasted bread or croutons (for serving)
• 1/2 lemon juice
• 2 tablespoons mayonnaise
• 1 teaspoon Dijon mustard
• 1 teaspoon whole grain mustard
• 1 tablespoon fresh parsley (chopped)
• salt (to taste)