PREHEAT the oven to 325F. Lightly grease a 6” round cake pan and set aside.
WHISK in a large mixing bowl, together eggs, water and oil. Add baking mix and combine.
POUR half of the batter into the prepared pan and smooth into an even layer.
SPREAD 1/3 cup of jam over the batter, leaving about 1” between the jam layer and the edges of the pan.
POUR the remaining batter over the jam layer and spread into an even layer (covering the jam completely).
BAKE 50-60 minutes, until firm and slightly cracked and domed on top.
REMOVE from the oven and cool in the pan 5-10 minutes. Then, remove the cake from the pan and transfer to a wire rack to cool completely.
Once the cake is cooled, MAKE the glaze by warming the remaining 2 ½ Tbsp jam in the microwave or on the stove until liquid. Whisk in ½ Tbsp water until smooth.
Immediately before serving, TOP the cake with your berries (use toothpicks to anchor a few in place if you find that they are tumbling off of the cake), the pour the glaze over the berries.
SERVE immediately