A quick and tasty way to cook and serve your favourite cephalopod (or maybe some scallops!)...
...either fresh (raw) squid, or octopus which you've gently braised the night before, or during the day (this takes 1 to 2 hours to simmer, see my method on preparing octopus). This is also extremely good with pan-seared scallops if you're not a fan of octopus or squid (optional garlic and capers with the scallops!).
So, you've cooked your octopus (or have your squid prepared and ready to go), now what?
This serves two people as a starter, 185 calories per portion (see serving suggestions for making this more of a meal) and used half of an octopus (400-500g, weight after preparation).
120g cooked octopus (head and/or tentacles, sliced into strips about 3/4 cm thick, on the long diagonal if slicing the tentacles) 
(or substitute raw squid, cut into rings / tentacles divided and trimmed or even plump, juicy scallops)
1 tsp neutral oil (e.g. sunflower, for Paleo use macadamia/avocado etc.) 
15g / 1 tbsp (salted) butter (or more to taste) 
2-3 garlic cloves, finely chopped 
1 tsp capers, very roughly chopped 
Squeeze of lemon juice, to taste 
Handful of flat leaf parsley leaves, roughly chopped 
Sea salt, and freshly ground black pepper 
Tasty served with a fresh green salad, and crusty bread, or even frites if you want to make it into more of a meal. You could swap the capers for some smoked paprika, and serve it as a tapas dish alongside other tapa.
Heat the sunflower oil over a medium to high heat in a good, non-stick pan. Add the octopus (or squid/scallops - which will only need a couple of minutes cooking before adding the other ingredients - don't overcook - and just turn the scallops once to caramelise each side - but ensure just cooked before adding other ingredients) and toss until it has acquired a little caramelisation, and is slightly golden in places.
Just off the heat, immediately add the lemon juice and capers, toss a couple of times (or stir) to coat, then toss/stir in most of the parsley.
Serve immediately with your choice of accompaniments, sprinkled with the remainder of the parsley.
I mostly used the head in this dish, with only a couple of tentacles, as some sources recommended discarding the head etc., so I decided to try it in a quick dish to see how it was. Please note, you can only see a half quantity in the pan shots, if you think it looks small! I much preferred the texture to squid, it was meatier, and less 'bouncy' and I cannot imagine why anyone would not use this part of the octopus. Octopus has a very mild flavour, more delicate than squid, I'd say. I frequently finish pan-seared scallops in this manner, minus the capers and garlic, and we often eat them straight out of the pan, they're so delicious!