Lightly grease 10" cast iron skillet with coconut oil.
Preheat oven to 350 degrees F.
Place strawberries and raspberries on the bottom of skillet. Sprinkle with two tablespoons brown sugar and gently toss (you can do this step in a bowl but doing it in a skillet makes one less dish dirty!).
In a medium mixing bowl, stir together coconut, oats, brown sugar and salt. Add coconut oil and stir well.
Sprinkle the topping mixture over the berries.
Bake the crisp for 30 to 32 minutes, or until bubbly on the edges.
Let cool before serving.
Serve with a scoop of coconut sorbet or ice cream, if desired.