Heat a few inches of oil in a large pot over medium heat. Next to the pot, set up a baking sheet with a cooling rack on top.
In a large mixing bowl, whisk eggs, milk, oil, and vanilla until smooth. Whisk in flour, sugar, baking powder, salt and spices. Stir in apple pieces.
When oil is hot, drop large spoonfuls of batter into the oil. Fry two or three fritters at a time, flipping as needed, and fry until golden brown. Remove to the cooling rack and repeat with remaining batter.
While fritters are cooling, whisk together powdered sugar, milk, bourbon, and vanilla in a large mixing bowl. When fritters have cooled slightly, dip in the glaze and place back on the cooling rack. Sprinkle with flaky salt and let the glaze set.