In a bowl, mix drained tuna, oats, and egg.
Add salt, pepper, garlic, parsley, and optional onion.
Let the mix sit for 2–3 minutes so the oats absorb moisture.
Form into 4 patties using clean hands or a spoon.
Heat a pan over medium heat with a drizzle of oil.
Pan-fry the patties for about 2–3 minutes per side until golden.
