In a cast-iron pan or stainless steel pot, combine apples, lemon zest, lemon juice, cinnamon, maple syrup and butter. Simmer over medium heat until the apples soften, about 15- 20 minutes.
Transfer to a blender or food processor and blend to desired consistency. Served best warm.
NOTE: For the butter, look for Kerrygold brand if possible, which is a great grass fed butter and modestly priced. You will notice a difference when using grass fed butter, especially in recipes like these.