Although rhubarb is one of the first stalks — or technically, vegetables — to emerge after winter, harvesting may still be weeks away, depending on where you live.
Happily, crumbles are adaptable creatures. You can substitute other fruit, so long as you adjust the sugar content. For sweet cherries, berries and stone fruit, use about half as much sugar called for. For sour cherries, keep the sugar where it is.
Frozen fruit (rhubarb, berries or otherwise) works well here, too, and doesn’t have to be thawed first; just add a few minutes to the baking time. Frozen blueberries, preferably zipped up with the juice and zest of a lemon, will turn this dessert from rosy and tangy to inky and mellow.
You can use tapioca starch as thickener if you’re keeping strictly kosher for a holiday (cornstarch also works). You don’t need much really, just a few tablespoons to help the fruit bubble and condense into a syrupy, jamlike layer beneath the golden-brown topping.
And for that topping, I use almond meal and shredded coconut to replace the usual flour and oats. Then instead of butter I stir in some almond butter to hold it together, which deepens the nuttiness and gives it all a sandy, almost caky texture. Combined with the fruity filling, it makes for a soft, crowd-pleasing dessert with low-key PB&J energy. The recipe is simple enough that it doesn’t have to be a special-occasion treat.