Thaw the Frozen Tuna and dry well on paper towels. Slice and dry the tomato and beetroot on paper towels.  Cut the tomato and beetroot into strips. Combine the Tartare sauce and Thousand Island dressing in a small bowl. Trim the cheese slices to a round shape the size of the bun. Shred the lettuce.

Deep fry the hash browns.
In a non stick fry pan over medium low heat melt a generous amount of butter and cook the tuna by first rolling the edges for 20 seconds an edge and then frying for 30 seconds each side.
Rest 2 minutes. Cut to a depth of halfway 4 cuts across the grain.

Meanwhile toast the buns to light golden. Put a cheese slice on each bun (top and bottom) and grill till just melted.

To assemble ::
Bottom bun with Cheese
Add tomato and beetroot strips and set into the melted cheese.
Add shredded lettuce
Put on the Tuna. Open up the cuts so the sauce can go in.
Add 1 Tbs of thousand Island dressing and push into the gaps
Trim off one end of the hash brown to match the size of the bun and place on top.
Finish by adding the top bun that has melted cheese

Delicious. The best way to get a serving of fish I know of. A bit of dressing and a deep fried element, but everything else is pretty healthy.

The idea of cutting the beetroot and tomato into strips and setting into the cheese, is it overcomes the burger sliding apart.  Works well.

There are two things important in any burger. First, very little if any liquid escapes and two, it does not fall or slide apart easily. Can you eat it one handed while driving is the ultimate test. The closer you get to this without compromising taste or texture the better the build of the burger. This burger is not quite that because of the flaked tuna (two hands required) but no liquid should escape. Unless of course you add far too much dressing, and who doesn't.

4  Brioche Hamburger Buns
8  Cheese slices
4  Tuna steaks (frozen)
2  Tomatoes
4  Beetroot Slices
2  Tbs Thousand Island Dressing
2  Tbs Tartare Sauce
2   Leaves Ice Berg Lettuce
4  Frozen Hash Browns
Salted Butter

This recipe uses easily available frozen, tinned and processed foods found in most kitchens. Frozen tuna steaks are a really good product. Not premium tuna, not fresh tuna, but not expensive. There are two tunas. Canned tuna which is horrible. Dry, tasteless, and without a lot of mayonnaise inedible. Thats my opinion. Then there is fresh tuna (raw) either fresh or frozen. No doubt that fresh tuna from a quality fishmonger is fantastic, and it's expensive. The snap frozen stuff is pretty good. In fact its really good. And similar in price to budget steak. Woolworths sell the Brioche Buns. You can substitute any bun. But Brioche is best.

I quick thaw the tuna steaks in the vaccuum sealed packets in a bowl of warm water. Takes less than 15 mins.
Then dry and cook. Snap frozen on the boat and consumed within 30 minutes of leaving the freezer means there is no chance of bacterial growth. Allowing the safe consumption of rare (blue) tuna. A good reason to buy snap frozen. Else put your trust in the fishmonger. Most restaurants will no longer serve Tuna Blue (rare) for this very reason. The Tuna might be top notch but alas over cooked at an outragious price.