01 -
Preheat oven to 175°C. Generously grease a 33 x 23 cm baking pan or a 30 cm cast iron skillet. Evenly distribute blueberries, blackberries, and strawberries across the bottom. Sprinkle sugar evenly over the fruit layer, followed by an even layer of raspberry gelatin powder.
02 -
In a large mixing bowl, combine yellow cake mix, water, vegetable oil, eggs, and Greek yogurt. Mix on low speed for 30 seconds, then increase to medium-high and beat for an additional 2 minutes, scraping the sides of the bowl as needed.
03 -
Pour the prepared cake batter over the berry layer, ensuring even coverage. Gently tap the pan on the counter to release any trapped air bubbles and level the surface.
04 -
Transfer to the oven and bake for 35–42 minutes or until a toothpick inserted in the center comes out clean. Remove from the oven and allow to cool for 5 minutes.
05 -
Carefully run a knife around the cake edges to prevent sticking. Invert the cake onto a serving platter. Serve warm or at room temperature, optionally accompanied by freshly whipped cream or vanilla ice cream.