The world's best restaurant, Noma, serves fresh birch sap every spring in place of table water. It's a surprise for lips - cold, honeyed and exotic. Noma has managed to make birch trees hip, not hippie.
Birch sugar is now widely available in health-food stores and savvy delicatessens. I'm not convinced the processing is natural, but this hasn't stopped its roaring rise. The sugar is mainly made by boiling birch sap until it's viscous and adding several chemicals to help the process along. Judging by the brands available in our stores, my eyebrows note that some are industrially synthesised in labs using corn instead of birch, and shaky about chemical catalysts. Watch out for piracy, too. Newfangled fads attract trouble like a pedigree Chihuahua in heat.
Children's confectionery brands are also turning towards xylitol. There is some noise about the reduction of bacterial growth in the mouth after consumption of xylitol, relative to cane sugar and dried fruit. The idea, then, is that xylitol may help reduce cavities (but so, too, would reducing our fizzy-cola supply or remembering to scrub our gnashers more often). I'm keeping an open mind on xylitol, given its popularity among diabetics and health bloggers. But it ain't sharing a shelf with my maple syrup.
In theory, white sugar and xylitol can be interchanged without mathematical gymnastics. Good news for diabetics. In practice, it's a total diva. Xylitol can make a cake surprisingly crumbly, just like the bottom of a box of Rice Krispies. If you fancy yourself as a culinary MacGyver, you'll love the challenge of whipping it into submission. If not, here's a stonking good recipe to get you started.
Lightly adapted from my favourite chef's kitchen. Forgive me, Nige.
Don't ignore the cardamom seeds - it would be like making brownies without chocolate.
For the cake:
220g (9oz) firm coconut oil
200g (8oz) xylitol birch sugar
300g (12oz) ground almonds
150g (6oz) fine polenta
1 teaspoon baking powder
Juice and zest of 2 medium unwaxed oranges
13 green cardamom pods, seeds only
Decent pinch of sea salt flakes
Greek yoghurt, to serve
For the syrup, you will need:
Juice of 2 lemons
Juice of 2 oranges
4 tablespoons honey
Fire up your oven to 180°C, 350°F, Gas 4. Line an 8in x 8in (20cm x 20cm) brownie tin. I use baking parchment - some brands are better than others, it's best to shop around until you find one that suits you.
Using a blender or food processor, cream the coconut oil and xylitol birch sugar together. Then add the ground almonds, the eggs, the fine polenta, the baking powder, the orange juice and the orange zest, as many black seeds as you can coax from the cardamom pods and a pinch of sea salt flakes. Blend until smooth.
Scrape the cake mixture into the lined brownie tin and smooth the top with a spoon. Bake for 20 minutes, then reduce the temperature to 160°Celsius, 325°F, Gas 3 for another 40 minutes.
As soon as the cake is out of the oven, leave it to cool in the tin and make the syrup. Boil the lemon juice, the orange juice and the honey until the mixture is somewhat thicker than water. Ten minutes should nail it.
While the cake is still in the tin, prod little holes all over it with a metal skewer. Spoon over the hot citrus syrup and watch the cake drink every drop. Allow it to cool for an hour before slicing it into thick wedges and serving it with some Greek yoghurt. Unimaginably delicious.