Special equipment: four 8-ounce oven-safe jars
Preheat the oven to 350 degrees F.
For the filling: In a medium bowl, toss the strawberries with the sugar, cornstarch and lemon juice. Spoon the fruit into four 8-ounce oven-safe glass jars, or other similarly-sized oven-safe containers. (I like to use actual jam jars.)
For the topping: In another medium bowl, mix the flour, 1 1/2 tablespoons sugar, baking powder and salt. Add the milk and butter and, using your hands or a fork, stir together to form a dough. Crumble the dough in large pieces over the strawberries, dividing it evenly among the jars.
Brush the tops of the dough with a light coating of egg yolk, and sprinkle about 1/4 teaspoon of the remaining sugar over each jar.
Place the jars on a baking sheet or in a roasting tin (to catch any juices that might spill over), and bake until the fruit is bubbling and the dough is golden and cooked through, 25 to 30 minutes. The cobblers can be served warm or at room temperature, with a scoop of vanilla ice cream on top, if desired.