The berries in this are cobbled together with a shortbread cookie-like crust, which for me is the finest around, far better than an oat-based crisp (oatmeal cookies do nothing for me, see). Use any mix of berries you like. Canal House also recommends Italian prune plums for this, reducing the cornstarch to 2 teaspoons and adding a hint of cinnamon to the fruit. I’ve changed up the Canal House version here by suggesting other fruits and adding lemon juice for that excellent sweet-tart flavor.
In a small bowl, whisk together the flour, baking powder, and salt and set aside.
In a medium bowl with a wooden spoon, beat the butter with ½ cup of the sugar until well combined. Beat in the egg yolk and vanilla. Add the flour mixture and stir until well combined. Refrigerate the dough while preheating the oven to 375 degrees.
In another medium bowl, combine the remaining ½ cup sugar and the cornstarch. Add the berries and toss to gently coat.
Put the berries into an 8-inch square (or any shape) baking dish. Sprinkle the lemon juice over the berries. Drop the dough by heaping tablespoons over the berries, flattening the drops out so that they will bake through evenly.. These drops need not connect.
Bake until the berries are bubbling and the topping is golden brown, about 40 minutes. Let cool a bit before serving. Especially good at the end of a long day with vanilla ice cream.