Gluten-free rhubarb crisp is a simple, rustic dessert! A perfect mix of spring rhubarb, crunchy oats, nutty buckwheat flour, and lots of butter. Serve it warm with a scoop of your favorite ice cream!
Preheat the oven to 350ºF (180ºC). Lightly grease an 8-inch (20-cm) square or round baking dish with butter.
In a large bowl, stir together the chopped rhubarb and lemon juice.
Mix together the sugar and cornstarch in a smaller bowl. Sprinkle the mixture over the rhubarb. Stir well to combine then set aside.
In a second larger bowl, combine the buckwheat flour, brown sugar, oats, cinnamon, and salt. Mix everything together with your hands, breaking up large chunks of brown sugar by rubbing them together with your fingers.
Add the butter to the oat mixture. Again with your hands, rub the butter into the oats. The topping is ready when all of the butter has been incorporated, and no dry bits of buckwheat flour remain in the bottom of the bowl.
Give the rhubarb a good stir then pour it into the prepared baking tin. Spread the rhubarb out into an even layer, then top it all over with the buckwheat mixture. Place the crisp in the oven and bake it for 40 to 45 minutes, or until the top is golden and the rhubarb is bubbling for at least five minutes. Cool the crisp on wire rack for 15 minutes before serving warm with ice cream or whipped cream.
Notes
Wash rhubarb well before chopping.
To use frozen rhubarb, there's no need to thaw first. Simply proceed with the recipe as written.
If your stalks of rhubarb are huge, slice them in half lengthwise before chopping into chunks.
I mix the sugar and cornstarch in a small bowl before adding them to the rhubarb. This method ensures an even, lump-free coating, however, add them straight to the rhubarb without pre-mixing if you want.
Let the fruit bubble in the oven for a minimum of five minutes to help ensure a properly thickened filling.