Heat oven to 375 degrees. Butter a 9-inch pie plate and set aside.
In a large bowl, toss rhubarb, strawberries, lemon juice, sugar, cornstarch and a pinch of salt. Pour into prepared pie pan. Sprinkle granola evenly over the top and drizzle with melted butter. Bake for 40-50 minutes or until fruit is bubbling.
Serve warm with whipped cream or ice cream.
