Place all fruit into a bowl and sprinkle with brown sugar. Stir gently to combine.
Transfer the fruit and sugar mixture to an 8x8 baking dish.
For the topping:
Combine all topping ingredients and mix together. You can use a fork or rub it together using your fingers.
For the crisp:
Sprinkle topping over fruit mixture in baking pan. Bake for 30 - 45 minutes, until topping is lightly browned. If you prefer a darker, crisper topping you can bake it a little longer, but the fruit will get softer.
Allow fruit crisp to cool for 5-10 minutes before serving.