Soften the vegan butter at room temperature so it is still firm, but pliable

Prepare the apples by peeling and coring them (*see video I like to use the apple skins in one long ribbon while cooking)

Add chopped apples & that ribbon of apple skin to a medium sauce pot with the water and sugar of your choice

Cook the apples over medium to high heat with the lid on for about 10 minutes to rapidly boiling, Take off the lid and reduce the heat to a simmer until the apples are translucent & mushy.

Remove from heat and remove the ribbon of apples skin(s)

Transfer the apples to a blender with about ½ cup of the plant milk and the cornstarch and puree smooth

Transfer the apple puree to the same sauce pot that you cooked the apples & add the remaining plant milk.

Return to the stove over medium to high heat whisking constantly until it comes to a boil.

Add the vanilla extract and then strain through a mesh strainer onto a sheet pan (no parchment paper or grease!)

Refrigerate the custard until it is completely cold & set

Meanwhile whip the vegan butter & salt with an electric mixer with the whip attachment until it is aerated & light and fluffy and starting to look whiter in color (about 5 minutes) scraping the bottom & sides of the bowl often

Add the sifted confectioners sugar and whip for another minute or two until smooth scraping the bottom & sides of the bowl often

Add the cold custard to the vegan butter while continuing to whip on high speed until all the custard is incorporated, scraping the bottom & sides of the bowl often

Continue whipping until the buttercream is smooth & silky