Gently mix the berries with sugar, salt, flour, and lemon juice. Pour this mixture into a 2-quart baking dish (or you can use a pie pan).
In a small bowl, combine the butter, brown sugar, flour, salt and oats. Use your hands to smash the butter into the flour, sugar, salt and oats until you have a sort of crumbly dough. Scatter the crumbly topping over the berries. It won't cover the whole top, and that's OK. Just distribute the crisp topping as evenly as possible. Bake for 30-40 mins. When the berries are bubbling and the crisp topping is browned and crisp-y, it's done.