Lightly season the shrimp, squid, and scallops with salt.
Melt the butter in a large skillet over medium heat.
Add the chopped onion and garlic, cooking for about 2 minutes until fragrant.
Add the shrimp and cook for 1 minute.
Pour in the chicken broth and lemon juice, then increase the heat slightly and simmer for 1 minute.
Stir in the heavy cream and cook until the shrimp are almost fully cooked.
Add the squid and bay scallops, cooking for 2–3 minutes until just opaque and tender. Avoid overcooking the seafood.
Taste the Mixed Seafood in Creamy Garlic Sauce and adjust the seasoning with salt and freshly ground black pepper.
Stir in the chopped parsley and remove the skillet from the heat.
Serve immediately with rice, fried green plantains, crusty bread, or a fresh tomato salad.