Mix together flour, oats, brown sugar, salt and cinnamon with the melted butter. Press ½ the mixture into a lightly greased 9”x9” baking pan or pie plate.
Spread rhubarb and strawberries over base.
Mix sauce ingredients in small saucepan and cook and stir over medium heat until thickened. Pour sauce over rhubarb. Sprinkle remaining crumbs over top and press down lightly.
Bake at 350º for about 1 hour.
Notes
In our family cookbook, the recipe comes with this note from Mom:
"I got this recipe at least 30 years ago from a magazine in a Toronto newspaper that no longer exists. I haven’t found one I like better for rhubarb! It can be made gluten free by using quinoa flour instead of the regular flour. If you can handle kamut flour, that also works well."
(Anna's note: For gluten free purposes, also ensure you have gluten free oats, such as Bob's Red Mill).
Recipe by Hidden Ponies at https://hiddenponies.com/2012/06/strawberry-rhubarb-crumble/