i've just returned from a fantastic solo trip to costa rica for surfing and yoga (more on that later)! the flower gardens are in full bloom and shared vegetable garden is booming with tomatoes, eggplants, peppers, cucumbers, tomatillos and zucchini. the local blackberries are peaking, sweet juicy and huge and the rush is on to pick and freeze as many as possible! this delicious cake was born of delight for berries, love for dylan (happy birthday baby) and ease of preparation (no sleep, long travels). it is a simple cake, the berries add flair and the tiny bits of chocolate are hidden little surprises. i prefer polenta over cornmeal for baking; pulsing it in a blender means it will have a fresh vibrant taste and creative texture. we are lucky to have fresh local goat buttermilk, a store bought buttermilk will work just as well, choose a good brand. i'm guessing blueberries would be fabulous here as well and its worth experimenting with your favorite flavor of chocolate. as a side note, i almost added 1/2 tsp of minced fresh rosemary, next time! buen provecho!
Preheat oven to 375. in a small bowl, gently fold together blackberries, rapadura sugar and chocolate pieces, set aside.
Add polenta grains to a blender, pulse till you have a mix of fine powder and semi-course grains, 10-20 seconds. measure out 1/2 heaping cup of the polenta cornmeal, save the rest for another baking project. sift together ground polenta, whole wheat pastry flour, sugar, baking powder and salt. add any remaining chunks from the sifter to the bowl and gently whisk flour mixture till incorporated.
Meanwhile, melt butter and whisk together with the eggs and buttermilk. with a soft hand, whisk into the flour mixture. you will have a thick yellow-hued batter.
Place the cast iron skillet and 1 Tbl of butter into the oven to melt the butter and heat the pan, 3-5 min. remove from oven add the batter using a spatula to spread it evenly across the bottom of the skillet. spoon the reserved blackberry mixture over the top and return to the oven. bake 30-40 minutes till edges and center are a golden brown. let rest 10 minutes. serve hot or room temperature.