This recipe is a slight modification of my grandmother's popular Jewish Apple Cake Recipe (for those of you who don't like change, I've made notes so you can make it exactly as her recipe is written!).Be sure to check out the how-to video!
Preheat oven to 350F (175C) and lightly grease the sides and bottom of a 9x13 baking pan.
Prepare topping by whisking together ½ cup sugar and 1 tablespoon cinnamon. Measure out just 2 tablespoons of the mixture and pour over your apples. Toss until all apple pieces are coated and then set aside.
In a separate large bowl, whisk together flour, sugars, baking powder, cinnamon, and salt until well-combined.
Make a well in the center and add oil, butter, eggs, buttermilk, and vanilla extract. Stir the liquid ingredients together until combined and then carefully fold the dry and wet ingredients together until well-combined (but don’t over-mix).
Add apples and stir until combined.
Spread batter into prepared pan and sprinkle the top evenly with remaining topping mixture. Transfer to 350F (175C) oven and bake for 40-45 minutes if using a metal pan or 50-55 minutes if using a glass dish. Cake will be done when a toothpick inserted in the center comes out clean or with a few moist crumbs (no wet batter!). Since it’s a somewhat dense cake, sometimes I like to use a knife to make a small cut in the center of the cake and make sure it’s baked through.
The Old-Fashioned Way:
My grandmother's recipe was done by mixing together the cinnamon, sugar, and apples first and setting aside. She used all granulated sugar and no brown (2 1/2 cups/300g total), all oil and no butter (so 1 cup oil total) and orange juice instead of the buttermilk. Half the batter was layered into the pan, then the apple/cinnamon/sugar mixture, then the rest of the batter, and it was baked for approximately 1 1/2 hours.
This recipe may be made in a well-greased bundt pan. Toss the apples and topping mixture together and portion half the batter, then the apple/topping mixture, then the rest of the batter and bake approximately 1 1/2 hours.
Store in an airtight container (or covered with foil or plastic wrap) at room temperature for 5 days. May be frozen for several months.