Glistening in righteous expensiveness in the upper-crust supermarkets, lives Mostarda di Cremona. What we can buy, while still the genuine article, is the lower end of the range. It’s a strange substance, candied fruit preserved in a mustard syrup. The Real Thing is split by region (there are many Mostardas) and also by specified fruit. You’d choose the one to go with your cheese or cold meat, like we would make a choice between quince or cranberry or mint jelly. It’s as much texture as flavour, some are chopped small and are more like an old English chutney, but I like the ones that look like a box of Newberry Fruits tipped into a bottle of glycerine.
When we were making Courgette and Pineapple jam, I loved the crispness of the courgette pieces in among the clear syrup, and I thought then that I’d have a go at a Courgette Cremona. Starting to research recipes, I discovered what my main problem would be. Authentic Mostardas are flavoured with mustard essential oil, which you can get in Italy but not here. There were compromise versions with dry mustard powder dissolved into the liquid, or spice bags filled with mustard seed boiled up with the fruit, but I was stomping my Ickle Foot of Tantrum. Why can’t I get it here? My Indian cookery books all talk about mustard oil with gay abandon, surely I could find it in Sheffield.
And I did, sort of. Mustard oil IS sold in Indian shops, in with the almond oil and hair tonics. It has “For External Use Only” written on the labels in bright red letters. Apparently under EU regulations it can’t be sold as a foodstuff, as it has a high amount of erucic acid. But they haven’t put anything in it to make it unusable, just a label saying Ooooh, Aren’t You Naughty. There’s a wonderfully tactful explanation on the Spices of India website. I wasn’t sure what the mustardy strength of my massage oil/hair tonic would be compared to this mythical Italian essential oil, so we took it slowly and tasted as we went.
Following the original jam recipe, I put 2 lbs of peeled and degorged courgettes, green and yellow, into a bowl and added about 1.5 lbs of caster sugar. I’d found that to be incredibly sweet when I made it before, so this time I added 2 fl oz lime juice as well. Stirred it up well, and left it overnight. The sugar brings out the juice, crisping up the courgette and also making a clear syrup. The idea is that now you boil the mixture, and it turns into jam. I wanted to stop partway through that process, while there was still plenty of liquid. It took a while to get there, but eventually I had some nicely candied courgette in hot syrup. I added a small tub of glace cherries (rinsed), 4 oz diced peel (not the regular industrial mixed peel, some candied citron, orange and lemon peel strips cut to the same size as the courgette), and simmered that for just a few minutes to meld it all in.
Now came the tricksy bit. The one thing I did know about mustard oil from my reading is that it is pungent in the bottle, but loses that and becomes sweet when you heat it. Fair play, regular made-up mustard does that too. So I didn’t want to heat it too much when mixing it in with the syrup, but I did want to get it emulsified before anything started to caramelise.
I waited until the syrup was warm enough to stick a finger into, and added 1 fl oz mustard oil. It tasted fine, sweet and slightly warming, but not anywhere near a full mustard hit. The mixture didn’t separate, though. Let it cool down a bit more, taste again, add some more oil. Over the course of a couple of hours I added 4 fl oz in total. The syrup is tangy rather than hot, certainly not piccalilli strength. It made a 1-litre jarful, and it looks beautiful. The light colours of the courgettes are set off by the deeper yellows and oranges of the peel, and the scattered bright red of the cherries. I was concerned that the syrup and oil would separate when it cooled thoroughly, but it doesn’t seem to have yet. Which means the mustard oil is slowly finding its way into the fruit …
The traditional Italian time to eat Mostardas is autumn, but I think for UK versions it’ll be Christmas. With ham, with Wensleydale, with cold turkey. Glazing a ham with it, even, or studding the top of a terrine – decorating the top of a warm whole Camembert.
We have a lot of butternut squash coming off the allotment, and I am tempted now to try a cross between candied pumpkin and a mostarda, but using the dry powder variant to see if I can get it stronger.