Wash hands with soap and water.

In a shallow 2-quart baking dish, combine 1 1/4 cups sugar and cornstarch*. Add rhubarb, raspberries, and lemon juice - mixing gently but thoroughly.

Meanwhile, in a food processor or a bowl, whirl or rub together with your fingers the matzo meal, the remaining 1/2 cup sugar, margarine, and nutmeg to create fine crumbs.

Squeeze matzo mixture to compact into lumps, then crumble over rhubarb mixture.

Baked in a 375 °F oven until cobbler is bubbling in center and top is golden brown, about 1 hour. Let cool 15 minutes.