Tuna Fish Cakes

Ingredients:

2½ oz. tuna
1 c. baby gem lettuce
¼ onion
2 tbsp. scallions
1 tbsp. sriracha
1 tsp. garlic
1½ tbsp. butter
2 tbsp. parsley
¼ c. sour cream
1 egg white (beaten)
1 tsp. lemon zest