The first time I tasted a kumquat, I was startled by the contrast between the tender, sweet rind and the intensely sour flesh.

The lingering tang proved addictive, though.  Soon I found myself regularly wandering by my neighbor’s kumquat tree, searching for a tiny fruit or two to filch – just enough to satisfy my craving but not so many that they would miss them.  I’d pop one whole into my mouth and wait for the bright shock of citrus flavor evoking fresh limes and clementines.

That dwarf tree was my only source for years.  I never saw kumquats at the grocery store.  Now, they’re more widely available and one Central Valley grower  sells them at the Santa Cruz farmers market.  I don’t even try to resist, despite the price.  After all, $6 a pound goes pretty far when the flavor is so concentrated.

Although they’re technically a winter crop,  kumquats are available throughout the spring in California.  They’re the perfect accent to rhubarb and strawberries in this classic crisp.

The sharp, acidic flavor plays the same role as lemon juice, complementing the strawberries and playing up the pleasant bite of the rhubarb.

I adore crisps made with spring fruit.  Last year, I offered one made with rhubarb, strawberries and cherries.  While rhubarb and strawberries are traditional companions in spring pies and crisps, kumquats bring a little extra spice to the party.

If your sweet tooth loves a sour contrast, this is the crisp for you.  You can always substitute the grated zest of a lemon or lime for the kumquats if you can’t find them.   I’d cut the sugar by a couple of tablespoons, however.

The topping for this crisp is the easiest yet.  Taking a tip from Dorrie Greenspan’s cookbook, “Baking, From My Home to Yours” (Houghton Mifflin, 2006), I’ve melted the butter before stirring it into the flour, oats, brown sugar and chopped walnuts.

Warm from the oven, topped with a scoop of good vanilla ice cream, this crisp is everything I want in a simple spring dessert – just in time for Memorial Day.