Create ice bath with 1 medium and 1 small sheet pan; set aside.
Beat egg yolks in small bowl until pale.
Combine sugar, flour, spice, and milk in large sauce pan. Whisk until smooth
Add apples and cook over medium heat until thickened and begins boiling, stirring constantly.
Once apple mixture is boiling, slowly temper egg yolks until warm to the touch. Pour heated egg mixture back into saucepan and boil for 3 minutes, stirring continually.
Remove saucepan from heat, stir in vanilla.
Pour onto chilled sheet pan, cover with plastic wrap directly touching and covering all surface area; refrigerate.
To use, mix gently and scoop or pipe as needed.
Notes
Store in the refrigerator for up to 5 days, tightly covered or completely encased. Do not freeze.