Perfect for a springtime get-together or picnic, these sweet, buttery bar cookies make a delicious hand-held treat. Fresh rhubarb adds a tart note that balances out the richness of the shortbread-like crust. Rhubarb is at its peak in the spring. If you can’t find it at the grocery store, you can substitute 1 cup of sliced strawberries or make the bars with raspberries only. Although these bars are all about the fruit, the crust is made with toasted ground almonds and the filling is flavored with almond extract, which adds a subtle nutty flavor and sweet aroma. When making these bars, be sure to line the pan with enough aluminum foil that it extends over both sides. The excess foil acts as handles to help you easily lift the baked bars out of the pan. Planning ahead for a party? Bake the bars 1 day in advance. Let them cool completely, then cover with aluminum foil and store at room temperature.