Gluten-Free Sourdough Polenta-Apple Cake

Adapted from http://you-name-it-free.blogspot.com/2009/01/tender-elstar-apple-cake.html

(Timeframe: 3-4 days.)
9x13” cake

Ingredients (always have all ingredients at room temperature to assist yeast development):

* 1/2 cup corn flour or cornmeal
* 2-3 cups water kefir, milk kefir, or yogurt, divided

* 1 1/2 cups polenta
* ½ cup brown rice flour
* ¼ cup sugar

* ½ cup cashews, walnuts, or pecans
* 2 tbsp fresh flax meal (opt.)
* 6 crisp Elstar apples, or your favorite local variety
* 2 tsp baking powder
* 1 lemon
* ¼ cup sunflower oil
* 1/3 cup agave syrup (or sweetener to taste)
* 2 eggs, lightly beaten
* 2 tsp cinnamon
* ½ tsp grated nutmeg
* 2 Tbsp. Maple syrup, to drizzle on top

Starter:
1. Mix corn flour and 1 cup of kefir/yogurt in a clean glass container until it is moist and gooooshy. Cover loosely with a cloth and set in a warm place for 1-3 days, until bubbly and fluffy, stirring at least once daily.

Batter:
1. When the starter is ready, mix together the polenta, rice flour, sugar, and 1-2 cups kefir (at least 1 cup, and the rest can be water), or as much as you need to make a stirrable mix
2. Add starter, mix well, and cover in a warm place for at least 12 hours.
3. 2-4 hours before baking, activate your nuts by soaking them in water. Drain water when finished and grind the nuts into coarse pieces.
4. Add 1/3 cup water to the flax meal in a sauce pan, and bring to a simmer over low heat, stirring occasionally. Let simmer for a few minutes, remove from heat, and let cool, continuing to stir occasionally.
5. Slice the apples into medium-thin slices, squeezing juice of half a lemon on them and tossing to prevent browning as you go.
6. Preheat oven to 350 F (175 C)
7. Add baking powder to the batter, along with the nuts, agave, eggs, the flax meal mixture, cinnamon, nutmeg, oil, and all but 10 or so slices of apple.
8. Pour batter into an oiled casserole or cake pan, and arrange the leftover apple slices on top.
9. Dust with cinnamon and nutmeg and a little sugar.
10. Bake for 10 minutes and turn the heat down to 325 F (162 C).
11. Bake for 30 minutes, or until firm. Drizzle with maple syrup mixed with the juice of half a lemon.