In a 9×9 baking dish, mix peaches, blueberries and basil with sugar, flour and salt. Toss well and set aside.
In a large bowl, whisk together oats, brown sugar, flour, cinnamon and salt. Use your fingers to add in the softened butter, crumbling it together until it’s evenly distributed. Sprinkle the crisp over the peaches and berries. Bake for 25-30 minutes, until crisp is golden and fruit is bubbly.
Serve immediately with ice cream and more fresh basil if desired.