Serve warm, scooped into bowls. If you’re traveling, cover the cooled pan tightly with foil, wrap in a clean kitchen towel for a little insulation, and rewarm gently in a 300°F (150°C) oven for about 10–15 minutes once you arrive, if desired.
For a nutty crunch, sprinkle 1/2 to 3/4 cup chopped pecans or walnuts over the cake mix before adding the butter. If you like a bit more sweetness and texture, add 1/4 to 1/3 cup granulated sugar mixed with 1 teaspoon ground cinnamon and sprinkle it over the cake mix before baking. For picky eaters who prefer things less tart, stir 2–3 tablespoons of sugar into the blueberry pie filling before spreading it in the pan, or use a pie filling labeled “extra sweet.” If someone in the family doesn’t love blueberries, you can swap one can of blueberry pie filling for cherry or apple to make a mixed-fruit version that’s still very travel-friendly. To cut some richness, use 6 tablespoons of butter instead of a full stick and lightly mist the top with cooking spray to help the dry mix brown. For a slightly fancier look at holidays, dust the cooled cake lightly with powdered sugar right before serving. This recipe also works well in two 8×8-inch pans if you want one to bring and one to keep at home; just divide everything evenly and start checking for doneness around 35 minutes.
