A little sunshine in winter: Toss these 4 ingredients together and let them turn into a cozy, bright dessert night.

Lightly grease the insert of a 4- to 6-quart slow cooker with butter or nonstick spray to prevent sticking and make serving easier.

In a medium bowl, whisk together the lemon cake mix and milk until no dry pockets remain. The batter will be pourable but slightly thick.

Whisk in the melted, slightly cooled butter until the batter is smooth and glossy. Avoid overmixing; you just want everything evenly combined.

Scatter the frozen blueberries evenly over the bottom of the prepared slow cooker. There’s no need to thaw them—using them straight from the freezer helps them hold their shape as they cook.

Pour the lemon batter evenly over the blueberries, using a spatula to nudge it gently toward the edges. Do not stir; you want the blueberries to form a juicy layer underneath the cake.

Cover the slow cooker with the lid. Cook on HIGH for 2 to 2 1/2 hours, or on LOW for 3 1/2 to 4 hours, until the top is set and springs back lightly when touched in the center. The edges will pull slightly away from the sides, and a toothpick inserted into the cakey portion (not the saucy blueberry layer) should come out mostly clean.

Turn off the slow cooker and let the cake rest, covered, for about 10 minutes. This allows the texture to settle so you get a nice contrast between the fluffy cake and the saucy fruit underneath.

To serve, spoon warm portions straight from the slow cooker, making sure to scoop down to the bottom to capture both the lemon cake and the blueberry juices. Pair with whipped cream, ice cream, or yogurt if desired.

Because this recipe is so streamlined, it’s easy to adapt to your pantry and preferences. For a slightly tangier profile, swap half of the milk for plain Greek yogurt or buttermilk; this will give the cake a tender crumb and a flavor closer to lemon pound cake. If you enjoy a stronger lemon presence, add the finely grated zest of 1 lemon to the batter before cooking or drizzle the finished cake with a quick glaze made from powdered sugar and lemon juice. You can also experiment with the fruit: substitute part of the blueberries with frozen raspberries or blackberries for a mixed-berry version, or use frozen cherries with the lemon cake mix for a brighter, almost cobbler-like dessert. For a bit of texture, sprinkle 1/4 cup sliced almonds or shredded coconut over the batter before cooking. If you need to keep the dessert dairy-light, you can use a neutral non-dairy milk and a plant-based butter; just know the flavor will be slightly different, so consider adding extra lemon zest or a splash of vanilla to keep it aromatic. Finally, if you prefer a firmer, less saucy base, reduce the blueberries to 1 1/2 cups or cook on HIGH toward the shorter end of the time range, checking early so the cake doesn’t overcook along the edges.