-
Position rack in middle of oven. Preheat the oven 350°F (180°C). Coat the inside of a 9-inch (23 cm) springform pan with nonstick spray; set aside.
-
Combine milk and lemon juice and set aside for 5 minutes to thicken in a large bowl. Meanwhile, place all of the berries in a non-reactive bowl, sprinkle with 2 tablespoons of sugar, then use a potato masher to lightly crush the berries. Set aside and juices will begin to exude, which you want.
-
In a separate bowl, whisk together the flour, cornmeal, baking powder and salt to aerate and combine. Set aside.
-
Going back to the thickened, soured milk, whisk in the melted butter and oil, then whisk in the remaining 2/3 cup (131 g) sugar and the eggs until everything is well combined and smooth. Whisk in dry ingredients until a few floury streaks remain, then add about three-quarters of the berries and any juices (you can do this by eye), switch to a silicone spatula and fold all the ingredients together well.
-
Scrape the batter into the prepared pan and top with the remaining berries and their juices.
-
Bake for about 35 to 40 minutes until cake is golden brown and a toothpick inserted in the center comes out clean. Cool on rack for 5 minutes, then unmold from pan. Cake may be eaten warm or cool to room temp. It is best enjoyed the day it is made but leftovers can be wrapped in foil and kept at room temperature for a day or two.