– 4 cups thinly sliced rhubarb – 1/2 cups granulated sugar – 1 Tbsp finely grated fresh ginger (alternatively use a teaspoon of good vanilla extract, or the seeds of a vanilla bean.) – 1 Tbsp cornstarch TOPPING – 1 cup all purpose flour – 1/3 cup granulated sugar (you could also use brown sugar) – 4 Tbsp unsalted butter, at room temperature