I know none of us have been out in the shops very much lately, but if you're anything like me you've made a few extremely essential trips out of the house to check out this year's Christmas sandwich offering.

Snackbar's Freddie Janssen | making your own Christmas condiments

Fredde Janssen

There are some pretty mad choices out there – a huge leap from the boring turkey and cranberry sauce sandwiches of days gone by: Pret is doing a hot roll with pigs in blankets; M&S are doing a truffled egg & ham sandwich; Waitrose are going all German Christmas Market on us with a smoked sausage and curry ketchup roll; and Costa, of all places, have a £5 (!) lobster toastie on their menu (no thank you.)

So if even the chains are getting creative, isn't it time we move away from the slightly sad, safe options too? I'm all for keeping traditions alive, but if cranberry sauce was really that great, wouldn't we be eating the condiment all year round?

Personally, I'm obsessed with condiments. A good pickle, chutney, kraut or sauce can make or break a meal. Having a fridge full of condiments means you can turn any quick mid-week meal into something special.

Fry leftover rice with some spicy and crunchy kimchi alongside a fried egg, and you've got a fab and nourishing meal in less than 10 minutes. Add a tangy sambal to your grilled cheese sandwich and you're at a jazzy cafe instead of just in your #WFH office; quick-pickle red onions in some lime juice and you've got the perfect topping for a taco; the list is endless.

If cranberry sauce was really that great, wouldn't we be eating it all year round?

When it comes to Christmas, I get most excited about the leftovers. Boxing Day is the ultimate eating and grazing day, minus the stress of cooking. It's all about making snacks out of all the leftover ham, turkey, platters of cheese and charcuterie – AKA, all the ingredients to make The Perfect Sandwich.

Sandwiches need condiments, and after making sourdough from scratch and countless banana breads this year, you are ready to switch things up a bit.

For example, why not make an umami mayo from leftover gravy – ideally you want to make the mayo from scratch, but since it's Boxing Day you'll be forgiven for just mixing a cup of (chilled) gravy with half a cup of Hellman's from the fridge, along with a spoonful or two of white miso and a splash of lemon juice.

For a genius twist on cranberry sauce, try a pear and apple mostarda. It's an Italian fruity-tangy-spicy condiment, made with fresh fruit and mustard, that pairs incredibly well with roasted meats, cheese, charcuterie and sandwiches. It's also a great way to use up leftover fruit before it goes bad.

Mostarda is made differently in every region in Italy. I make mine over several days to pull all the juices from fresh and dried fruit. You start with peeling and cutting fresh fruit into small chunks and cover it in sugar to release liquid. Cover diced dried fruit in water that's been simmered down a bit and add this to the fresh fruit mix.

View on Instagram

Leave this to rest for a day or so before you pour off the sugar syrup to which you'll add aromatics spices and fresh ginger, and reduce to a thick syrup before pouring it back over the fruit. After a day or so you should reduce the syrup again, until it's quite thick, before adding the fruit with mustard powder and (white wine or cider) vinegar – then simmer, reduce, and keep tasting and seasoning it until it's as sweet, tart and spicy as you like it to be.

The Italians also have giardiniera – pickled vegetables in oil and spices – a relish that's similar to the British staple piccalilli. I like to use red peppers, cauliflower, carrots, red onion, and courgettes, brined in plenty of white wine vinegar, bay leaf, juniper berries and rosemary, all topped with extra virgin olive oil. I can't think of a better accompaniment to a cheese plate than this.

Pickled currants (make a brine of red wine vinegar, sugar, salt and rosemary) over root veg like carrots and parsnips, or even with roasted brussels sprouts in a vinaigrette make an amazing side.

Speaking of sprouts, which are for me the epitome of Christmas – I highly recommend everyone try kimchi-ing their Brussels this year. Fermented for a couple days in a mix of Korean chili powder, garlic, ginger, soy and spring onion, this condiment can make a bold side dish that's super-seasonal, fun and delicious. Bye, cranberry sauce!

Get your hands on Freddie's ferments and sandwiches from Snackbar in Dalston. snackbarlondon.com