Wild watermint grows along our stream edge. It quietly rises from the banks and within the shallows in swathes during early April. We’re usually alerted to it’s seasonal arrival by accidentally treading on a patch of emerging leaves, releasing a heady aroma into the air. The flavour is reminiscent of peppermint, but perhaps with a little more sweetness in the leaves. This isn’t altogether surprising given that peppermint is actually the offspring of watermint and spearmint. In the kitchen, we find it works well in place of garden mint.
Up in the veg patch, the rhubarb crowns have been slowly pushing up electric pink stems streaked with sage green. They are now ready for pulling. A gentle tug will ease them cleanly from the base and a quick cut will remove the enormous frilly (poisonous) leaves from the top of the stem.
Both watermint and rhubarb are the key ingredients for what has become our favourite crumble recipe for this time of year. The flavour combination is inspired by a fantastic dessert of tangy poached rhubarb and refreshing mint granita that we ate at the restaurant Roast in Borough Market many years ago. We’ve suggested cooking the crumble separately from the rhubarb as this allows the biscuit topping to turn golden all over and become really crunchy. The result is tart-sweetness from the rhubarb, gingery warmth from the biscuit topping and freshness from the mint. A scoop of vanilla ice cream is our preferred accompaniment as it brings a little extra sugar to counter the sour rhubarb, plus some hot-cold temperature contrast.
Rhubarb, Wild Watermint and Ginger Crumble
For the crumble
- 130 g plain white flour
- pinch of salt
- 3 tsp ground ginger
- 80 g unsalted butter, cold and diced into small cubes
- 30 g ground almonds
- 50 g demerera sugar
For the rhubarb
- 600 g rhubarb
- 6 tbsp granulated sugar
- generous handful of fresh watermint leaves
- a few small watermint leaves
- vanilla ice cream
First make the crumble topping. Preheat the oven to 200°C. Sift the flour with the salt and ground ginger into a large bowl. Rub the butter into the flour mixture until it looks like breadcrumbs. Stir in the ground almonds and demerera sugar. Use your hands to lift, squeeze together, and ruffle the mixture through your fingers a few times to encourage some slightly larger clumps to form amongst the biscuity rubble. Empty the bowl onto a baking tray, spread out evenly, and pop in the oven for about 35 minutes, checking and stirring halfway through (at which point the mixture will clump together a little more and form some larger pieces), until golden brown. Leave to cool, stirring occasionally. It will crisp up a little more as the temperature decreases.
Meanwhile, cut the rhubarb into 3cm lengths and place in a single layer in a small roasting tin. Then blitz the granulated sugar and mint leaves together in a blender (or pestle and mortar), until the mint leaves have been crushed into the sugar, leaving it green-flecked and slightly damp. Scatter the mint sugar over the top of the rhubarb, cover with tin foil and put in the oven for 15-20 minutes until the rhubarb is cooked through and soft, but still just holding its shape.
To serve, lift a few pieces of rhubarb into a bowl and spoon over some of the bright pink juices from the roasting tin. Scatter over a couple of spoonfuls of the crumble topping, and decorate with a few baby watermint leaves. Serve warm with a generous scoop of vanilla ice cream.
We are always extra careful when wild harvesting ingredients for cooking. We never pick anything that we can’t identify and, if unsure, we consult the advice of our guide books. We particularly like the River Cottage handbooks, by John Wright, who pens his words in a way that is easy to understand, knowledgeable, and full of good humour. River Cottage Handbook No.7: Hedgerow, covers the wild ingredient in this recipe. Luckily watermint is an easy plant to identify and comes in plentiful quantity at this time of year. However, our watermint grows close by to the poisonous leaves of hemlock water-dropwort and lords and ladies plants, and although the leaves look very different, a lapse in concentration when picking could make dinner time most unpleasant, so we always exercise extreme caution.