Clean the rhubarb thoroughly and slice into ½” pieces and add to a large bowl.
Wash and de-stem the strawberries and cut into quarters (or ⅛” if they are on the larger side).
Add them to the bowl. Add the cornstarch, vanilla, salt and stir all together.
Add in the lemon zest and juice and mix. Let sit while making the topping.
Preheat the oven to 350 degrees.
In a large bowl, add the flour, brown sugar, sugar, salt and cinnamon and stir together.
Add the butter and using a pastry cutter, cut the butter into the mixture until it resembles crumbs.
Stir in the oats and pecans.
Spray a 9” x 13” pan with cooking spray. Layer in the fruit on the bottom and sprinkle the flour mixture over the top in an even layer.
Place in the oven and bake for 45-50 minutes, until the top is golden brown.
Remove and let cool.
Serve with your favorite whipped topping or ice cream!
Or even a drizzle of heavy cream!