Preheat the oven to 350 degrees F. Cut the apples into 1-inch pieces, and transfer to a large bowl. Add cranberries, lemon juice, and sugar, and toss to combine. Butter a 9×13 glass baking dish, and set aside.
In a medium bowl, combine all the topping ingredients and stir until combined.
Pour apples into the prepared dish. Spread the topping mixture evenly across the fruit. Bake until the fruit is soft and the topping crisp, about 35 minutes, watching carefully that topping doesn't brown too much. Let cool 15 minutes. Serve warm or at room temperature with vanilla ice cream or crème fraiche.
Preparation time: 1 hour
Recipe adapted by Julie Negrin from Jennifer Clair, Founder of Home Cooking New York and the author of Gourmet Cooking on a Budget (Globe Pequot Press, Spring 2010) with Michalene Busico.