Rhubarb Shortbread Bars

With Coconut Flapjack Topping

After a slow start this year, my rhubarb has started producing stalks again - it's keeping us in occasional desserts while I wait impatiently for my gooseberries to ripen. The usual midweek dessert is just cooked fruit with natural yogurt, but the weekends are always a little more relaxed as far as calorific treats are concerned.

This recipe was devised with two of the regular baking challenges I enter in mind. This month's AlphaBakes challenge is the letter R (and I make no apologies for using rhubarb again, it's that time of year!) and the Tea Time Treats challenge is to make flapjacks and traybakes.

The base was made by rubbing 80g unsalted butter into 200g plain flour and 40g caster sugar, and pressing the crumbs into the base of an 8" square tin, lined with baking parchment. I made a small raised edge in case the fruit produced a lot of juice, and baked the base for 15 minutes at 190C. Although I've used this shortbread base before, in the same sized tin, it didn't work as well this time, and was a little fragile - I'm guessing the topping held it together better last time. I think I needed a thicker base with more butter to bind it - something with the more classic shortbread proportions of fat to flour.

When the shortbread was cooked I sprinkled two tablespoons of ground rice evenly over the surface - I find this excellent at absorbing excess juice when raw fruit is used in this sort of baking. I then topped this with 350g rhubarb, diced into cubes of  0.5-1.0cm in size. Practically speaking, this meant splitting two large rhubarb stalks in quarters, lengthways, then chopping each length into 0.5cm pieces.

The topping was made by heating together 60g coconut oil and 60g coconut flower nectar (a low GI alternative to beet and cane sugar) until the oil had melted, then stirring in 100g of porridge oats and 20g desiccated coconut. This was sprinkled carefully over the fruit to give an even layer and then the whole thing was returned to the oven for a further 30 minutes at 180C, until the fruit was soft and the topping a golden brown colour. The traybake was cooled in the tin before cutting into portions.

Apart from the fragile base, I really liked these bars. The sweet and sticky flapjack topping was balanced nicely by the tart fruit and the crisp shortbread. I had worried that the fruit might need sweetening, but the balance between the layers was just right. The addition of coconut to the topping added an extra flavour element that worked surprisingly well - I don't think I've ever tried rhubarb with coconut before!

AlphaBakes (see the rules here) is hosted alternately by Caroline Makes and The More Than Occasional Baker, who is running this month's challenge. Tea Time Treats (see the rules here) is hosted alternately by Lavender and Lovage and The Hedge Combers, who is running this month's challenge. Both hosts post a round-up of entries to each challenge at the end of the month.