Melt 1 stick of butter and let cool.
Cut your apples into long slices, toss with 1 tsp cinnamon and ½ cup brown sugar. Transfer the coated apples into a large cast iron pan. (you can peel your apples, but I usually leave the skin on because we like the texture).
In a small mixing bowl, whisk together your flour, sugar, cinnamon, baking powder, and salt. Set aside.
In a large mixing bowl, whisk together your eggs, butter, sourdough discard, granulated sugar, and mix until fully combined.
Mix your dry ingredients into your wet ingredients and mix until just combined. Over mixing will lead to a denser topping.
Bake at 375 for 35 - 40 minutes, until the top is golden brown.
Serve warm with ice cream or whipped cream and enjoy!
