Rhubarb has been harvested for thousands of years, but rhubarb desserts are a relatively recent invention.

In fact, it wasn't until the 1700s, when sugar became widely available to common folks, that the super-tart stalk started appearing in cookbooks.

Cooked with water and sugar, rhubarb is used as an ice cream topping and made into jam. But it's most noted for its characteristics as pie filling, which is why some folks simply call it "pie plant."

Rhubarb pies made with strawberries or other fruit are common; the English enjoy pies made with rhubarb and ginger.

Fruitful question: By taxonomy, rhubarb is a vegetable, a member of the buckwheat family. But it's usually used as a fruit. A 1947 ruling in a Buffalo court settled the matter, at least when it comes to customs duties. A U.S. Customs Court judge ruled that rhubarb is a fruit, reasoning that since it's almost always used as one, it should carry the same tariffs as fruit.

Leave it alone: The stems are used in cooking, but the large leaves contain oxalic acid and can make you sick.

This recipe, from Gourmet, produces a tender, rich cake studded with fruit. It's the tangy flavors of strawberry-rhubarb pie, without all the work in fashioning a crust.

> Rhubarb Strawberry Pudding Cake

1/4 cup water

1 1/2 teaspoons cornstarch

1/3 cup plus 1/2 cup sugar

2 cups chopped fresh rhubarb stalks

1 cup chopped fresh strawberries

1 cup all-purpose flour

1 3/4 teaspoons baking powder

1/2 teaspoon salt

1 large egg

1/2 cup whole milk

1 stick ( 1/2 cup) unsalted butter, melted and cooled slightly

1 teaspoon pure vanilla extract

Put oven rack in middle position and preheat oven to 400 degrees. Butter an 8-inch square glass or ceramic baking dish.

Stir together water, cornstarch, and 1/3 cup sugar in a small saucepan, then stir in rhubarb. Bring to a simmer, stirring constantly, then simmer, stirring occasionally, 3 minutes. Remove from heat and stir in strawberries.

Whisk together flour, baking powder, salt, and remaining 1/2 cup sugar in a bowl.

Whisk together egg, milk, butter and vanilla in a large bowl, then whisk in flour mixture until just combined.

Reserve 1/2 cup fruit mixture, then add remainder to baking dish and pour batter over it, spreading evenly. Drizzle reserved 1/2 cup fruit mixture over batter. Bake until a wooden pick inserted into center of cake portion comes out clean, 25 to 30 minutes. Cool in pan on a rack 5 minutes before serving.