Add the rest of the butter to the pan with the syrup in which we cooked the apples. Melt the butter over medium-low heat.
Add while stirring: sugar, nutritional yeast, turmeric, paprika, tapioca starch, xanthan gum, agar powder, and salt; mix well.
Increase to medium-high heat, add the coconut milk while stirring constantly. Bring to a boil, cook for another two minutes until slightly thickened. Remove from the heat.
Open the vanilla stick lengthwise and add to the mixture. Stir for a few seconds. Next, take out the vanilla bean, scrape off the seeds with a teaspoon and add to the cream. Mix well. Let the cream cool slightly.
Pour the pastry cream over the apple filling and cool to room temperature. Cover with cling film and refrigerate for at least an hour.
Serve at room temperature or cold.