Preheat oven to 400F. Line a baking sheet with parchment paper and set aside.
In a mixing bowl, whisk together Bisquick, sugar, cinnamon, nutmeg, and allspice.
Add applesauce, milk, and egg. Stir to combine into a batter.
Add diced apples and stir to incorporate.
Scoop batter out into 12 rounds, placing each on the prepared baking sheet (I used a large cookie scoop for this). Transfer to preheated oven and bake for 11-13 minutes, or until golden-brown and cooked through.
While the fritters are baking, prepare the glaze by whisking together powdered sugar, vanilla extract, and milk.
Remove fritters from oven and turn on the broiler.
Using a pastry brush, brush a coating of glaze onto the tops of the warm fritters. Return the pan to the oven and broil for about a minute, which will cause the glaze to bubble up. Keep a close eye on them so they don't burn!
Remove pan from oven and let cool for a minute or two, then brush the tops of the fritters with the rest of the glaze. The glaze will harden to a satiny finish as the fritters cool.
Serve warm or allow to cool completely. Enjoy!