Heat approximately 4-inches of vegetable oil in a large heavy bottomed pot over medium heat until it reaches between 340 to 350ºF.
Meanwhile, peel, core, and dice the apples into about a ½ cm dice and set aside.
In a large bowl, combine the flour, sugar, baking powder, salt, cinnamon, and nutmeg and whisk well. In a separate bowl, whisk together the egg, buttermilk, melted butter, and vanilla. Add the wet ingredients into the dry and stir until almost combined. Add the apples and fold in to evenly distribute.
When the oil is heated, working in batches of 5 or 6, carefully drop heaped tablespoons of batter into the hot oil and fry until golden brown, flipping frequently. This should take 4 to 5 minutes. Remove the fritters from the oil and place on a rack lined sheet pan to cool slightly. Continue frying until all the batter is used.
Make the maple glaze by whisking together the butter, syrup, and icing sugar. If the glaze seems too thin, add more sugar; if it is too thick, add more syrup.
Dunk the warm fritters in the glaze and set back onto the rack lined sheet pan to allow the glaze to firm up.
Serve or transfer to a box or container and store on the counter for up to 2 days.
