In a bowl, stir the fennel seeds, paprika, garlic salt, olive oil, balsamic vinegar. Mix in the shrimp, add salt and pepper to taste, and let the shrimp marinate for about 10 minutes.
Dice the onion and garlic.
Heat the coconut oil in a large skillet over medium to medium-high heat. Add the black peppercorns and let them cook for 1 to 2 minutes. The pepper will pop in the hot oil, so cover your pan with the lid while they cook.
Remove the lid from the pan and sautée the onion and garlic with the pepper until they caramelize, and are soft and brown. Then add the shrimp, and let them cook for about 2 to 3 minutes on each side.
*In place of coconut oil, use butter or your preferred cooking oil for frying the pepper and shrimp.