Seafood Lasagna

Tomato sauce -
200g prawns
170g crab
1 large red onion
500g tomatoes
2 cloves garlic
100g black olives
8 mini gherkins
1 tablespoon of capers
balsamic vinegar
1 tablespoon of tomato puree

White sauce -
1/3 pint of milk
200g mascarpone cheese (light)
2 tablespoons of chopped fresh dill
1/4 grated lemon zest
1 small red onion

Wakame as replacement for pasta - 2-3 layers thick.
Basically just cook these sauces seperately then assemble. Cover on top with very thinly sliced onion and paprika

Verdict - 
Pretty damn good (and great the next day). Adjustments for next time - slightly less dill, bit more lemon.
Crab is a bit of a waste as overpowered - stick to prawns or maybe squid.
I blitzed the prawns, olives, capers and gherkins in food processor - bit too fine - next time just chop prawns.
Wakame works well but needs to be thicker - I wasted half a pack - should have put it all in and gone for 4-6 layers thick.
White sauce needs to be thicker - I'm going to try Xanthum gum as a thickener.

Next time would be good with parmesan cheese on top.

The numbers - 
Assuming you eat about 1/4 this per portion, this is roughly about 250 calories and 10g carbohydrates