Set rack in the center of the oven. Combine all of the topping ingredients into a food processor. Pulse until the mixture forms crumbles the size of small peas; do not over process. Set aside.
Pour the plums and apricots directly into a large, shallow baking dish and sprinkle with sugar and flour to coat evenly. Spread crisp topping over entire surface of fruit. Bake until fruit is bubbly and the top is golden brown, approximately 30 to 40 minutes. Serve warm or room temperature, plain or with ice cream.
Make the topping ahead. In fact make a double or triple batch and freeze it in single recipe size packets so you can whip up a crisp on the spot, anytime.