Sauté the veggies and season them with salt, pepper, and paprika.
Add the tomato paste, crab, and enough seafood stock to cover the mixture, then cook.
Remove the crab and set it aside.
Blend the remaining mixture until smooth.
Stir in the heavy cream and adjust the seasoning with salt and pepper to taste.
In a separate bowl, combine the cream cheese, crab meat, shallots, chives, salt, pepper, cheddar cheese, and mozzarella cheese, mixing well.
Spread the cheese and crab mixture between two slices of the croissant loaf.
Toast the sandwich on all sides until it turns golden brown.
