Preheat the oven to 350 degrees. Grease an 8×8" baking pan or 9" skillet. Place the strawberries, rhubarb, sugar, orange zest and cornstarch in a medium bowl and toss to combine, then pour into the prepared baking dish.

Melt the butter in a medium bowl until melted, about 1 minute. Add the oats, flour, brown sugar and pinch of salt to the butter and stir just until combined.

Sprinkle the oatmeal crumble topping evenly over the fruit and bake for 45-50 minutes, or until the bubbly and golden brown. Check the crisp after 30 minutes of baking time and cover with foil if it begins to brown too quickly. Remove from heat and let stand at least 15 minutes to set. Serve warm with ice cream, if desired. Enjoy!