The original recipe for this came from a Better Homes and Gardens cookbook featuring kids' lunches. They had two versions, the "Mermaid Delights" using shredded carrots and dried basil, and "Buccaneer Burgers" using canned corn and dried dill. The idea is to stir in 1/3- 1/2 c. of some small bits of vegetable and 1/4 tsp. of an herb. Feel free to come up with your own! Canned salmon can be substituted for the tuna, if you like, as could about 4 ounces of any cooked fish. If you like mayonnaise on burgers, tartar sauce would be a good replacement here.
The patties didn't turn out as large as the book's photos showed, and today it dawned on me why. When the book was written, several years ago, a can of tuna weighed 6 1/2 ounces. They've shrunk since then, down to 5 ounces. I opened and drained two cans and weighed them to see how much actual meat was in there; each can held about 3 1/2 ounces tuna. So there you go. For larger patties, either just make three for each can of tuna you use, or make them thinner.
Mermaid Delights
1 (5 oz.) can tuna, drained
1 large egg
1/4 tsp. dried basil
dash of pepper
14 rich round crackers, crushed, OR about 1/3 c. dry bread crumbs
1 medium carrot, shredded
1/3 c. shredded cheese (you choose which kind)
4 slices of cheese (your choice)
4 hamburger buns (the ones above are homemade)
4 lettuce leaves
sliced tomato and/or pickles
Put tuna in a bowl and break into chunks. Mix in egg, then basil, pepper, and crumbs. Stir in shredded carrot and shredded cheese. Turn on the oven broiler.
Grease a cookie sheet, then scoop mixture into four (or three!) equal piles on it.
Shape into flat patties, about 3 1/2" across. Broil about 4" from heat, for 4 minutes or until browned. Either flip patties over and broil another 3-4 minutes, OR turn the oven to 375 degrees F and let them bake 10 more minutes.
Top immediately with a slice of cheese, then assemble burgers with the buns, lettuce, tomatoes, and pickles.