In a large mixing bowl, combine your unfed sourdough starter with all-purpose flour, mixing well. Gradually add water until the batter reaches a thick yet pourable consistency. Cover the bowl with a clean towel and let it rest overnight at room temperature.

The next day, check the batter, then add baking powder, salt, ground cinnamon, ground nutmeg, ground ginger, granulated sugar, and the egg. Stir until all ingredients are fully combined.

In a skillet over medium heat, melt the unsalted butter. Add the chopped Honeycrisp apples, along with a tablespoon of sugar and a sprinkle of cinnamon. Sauté for about 10 minutes, then remove from heat and let cool.

In a heavy-bottomed pot or deep skillet, pour enough canola oil to cover the fritters by about an inch. Heat the oil to 350°F (175°C) using a thermometer.

Once the apple mixture has cooled, gently fold it into the prepared batter.

Using a 1/4 cup measuring cup, drop portions of dough into the hot oil, frying in batches. Cook each fritter for about 2 minutes on one side, then flip and fry for another 2 minutes.

In a small bowl, whisk together powdered sugar and oat milk until smooth. Drizzle this glaze over the tops of the fritters.