Preheat the oven to 400 degrees F. For the filling: Combine the berries and plums in a mixing bowl. Add the brown sugar, flour, cinnamon and salt, and toss to coat. If your fruit is super sweet and in season, you may need less sugar. Pile the fruit mixture into four 8-ounce ramekins. For the topping: Combine the flour, brown sugar, oats and salt in a large mixing bowl. Next, cut in the butter with a pastry cutter or two forks, making sure that the butter stays chilled so you end up with a crumbly texture. Mix in the chopped pecans and spread evenly over the fruit. Bake until crisp and golden brown, 25 minutes. Allow the crisp to cool 20 minutes. Serve alongside ginger gelato.