For me, classic Moules & Frites.
Practically an institution in Belgium where there are a number of set recipes: Moules Marinière, Moules Parquées, Moules à l'Ail and so on, then the range of Chef's Signature pots of mussels.
I have my own favourite, which is a blend of Moules Marinière and Moules à la Crème: butter, onion, fennel, garlic, parsley, white wine and cream.
Frites should be Skinny Chips, or "fries", par-boiled to fluff up a little and fried off in duck fat for that authentic Belgian flavour. I love goose fat, as you know, and that will be my fat of choice.
Take a couple of potatoes, peel and cut into "fries". Skinny Chips, for us Brits.
Par-boil for three to five minutes, drain and allow to cool a little.
Don't "do" white potatoes? Well, pretty much any root will do the trick. For lower carb, leave 'em out and enjoy some greenage alongside - tenderstem broccoli would be ideal.
Take your mussels, wash them and discard any that are not closed.
Remove the beards and set aside.
Prepare your mise en place - getting all the ingredients cut and ready on a board: onion, fennel, garlic, parsley, white wine and cream. I tend not to drink white wine and didn't have a complimentary one in, so use Noilly Prat; posh Vermouth.
Don't "do" wine? Well, water will do just fine. It'll just be a bit bland, but you will get the real taste of the mussels as is, not enhanced.
You need a skillet and a lidded pan.
In the skillet melt some of your favourite paleo fat - goose fat, for me - and drop the frites in. Keep the heat on medium. Too low and they won't crisp, too high and they'll burn; along with the fat.
In the lidded pan, drop in a generous slab of your favourite butter. Bathe the onion and the fennel in it, dropping in the garlic, and as the heat rises, give the pan a generous slosh of wine (or Vermouth), pour in the mussels and get the lid on fast.
The mussels will cook through in the steam from the wine, taking on all those lovely flavours.
Give the pan a shake and toss in chopped parsley. Shake again. After a few minutes, the mussels will be cooked through - they will have opened and they'll be warm.
Remove the mussels into a bowl and remove any which have not opened.
Pour some cream into the juices in the pan. Raise the heat and reduce.
Don't "do" cream? Whisk in butter and reduce. Don't "do" butter? Well, just reduce to concentrate the flavours.
Once reduced, pour over the mussels, add a grind of freshly milled black pepper (no sea salt, since the flavour is delicate and already salty enough) and some more chopped parsley.
The sweetness of the mussels will be enhanced by the Vermouth, onion, fennel and garlic with the cream laying down a velvet backdrop, parsley just perfuming through.
Serve the frites alongside.
Dig in and enjoy, scooping out the mussels with half of the shell, slurping down the gorgeous sauce and mopping up with frites.
So, how do you like yours?