Boil the crawfish in a large pot of water.
Once cooked, drain and allow them to cool.
Remove the tails and set the meat aside.
In a large saucepan, heat olive oil over medium heat.
Add the crawfish shells, paprika, and cayenne pepper.
Saute for about 5 minutes until fragrant.
Add water to the saucepan and bring it to a boil.
Reduce heat and let it simmer for 30 minutes.
Strain the liquid into another pot, discarding the solids.
In a clean pot, melt butter and add the chopped onion, bell pepper, and garlic.
Saute until the vegetables are tender.
Stir in the flour and cook for a few minutes, ensuring it doesn't burn.
Gradually whisk in the crawfish broth, tomato paste, and heavy cream.
Let it simmer for about 15 minutes, stirring occasionally.
Add the reserved crawfish meat, season with salt and pepper, and cook for another 5 minutes.