Step 1

Preheat oven to 350°F if using a glass pan, or 375°F for a metal pan.  Lightly grease or spray a 13×9 inch pan and set aside.

Step 2

In a medium bowl whisk the sugar, flour, baking powder, salt and cinnamon. Using a pasty cutter, blend in the butter until the mixture resembles coarse sand. Add the beaten egg and mix until the dough starts to hold together but is still crumbly. Firmly press ⅔ to ¾ of the crumble mixture into the prepared pan.

Step 3

In a large mixing bowl whisk together the brown sugar and cornstarch. Add the orange juice, zest, rhubarb and strawberries and toss to combine. Pour the fruit over the crust and spread evenly. Crumble the remaining topping over the fruit squeezing portions together into larger clumps.

Step 4

Bake for 40-45 minutes or until the top is lightly browned and the fruit is bubbling. Cool completely. Whisk together the icing ingredients then drizzle over the top of the bars, if using.