Spread the shrimp shells and heads in a single layer on a half pan and roast in a 400-degree oven for five minutes.

Add the roasted shrimp shells and heads to a large stock pot with the white onion, carrots, celery, garlic, black peppercorns, bay leaf, thyme, and water.

Bring the contents to a boil on high heat, then lower the heat to low and simmer covered for 30 minutes with the lid slightly askew.

Strain the stock through a fine mesh colander into two large mason jars and set aside. This recipe makes 8 cups of stock, enough for two batches of bisque, or reserve it for other recipes.

Drizzle the avocado oil in the same stock pot over high heat, and saute the leeks, carrots, and celery for two minutes, then add the garlic and ground chipotle chile pepper.

Add the shrimp and cook until pink but still tender, 3 to 4 minutes.

Pour the dry sherry over the sizzling shrimp and reduce for one minute. Reserve a few shrimp to garnish.

Add the sauteed shrimp with vegetables to a food processor or high-powered blender, puree until smooth, and set aside.

Melt the butter over medium heat using the now-emptied stock pot. Then, stir in the flour to form a roux. Cook the roux for two minutes, then add the heavy cream.

Stir in the pureed shrimp from the food processor, the stock, the tomato paste, and season with salt and pepper.

Simmer for several minutes as it thickens.

Garnish with reserved grilled shrimp, thyme, or heavy cream drizzle, and serve with a warm baguette. Enjoy!