PARVE PASTRY BOSTON CREAM

​Ingredients:  6 egg yolks  2 cups of water ¾ cups of sugar vanilla and / or lemon zest  4 tablespoons of potato starch  Directions  You mix 6 yolks, two cups of water, ¾ cup of sugar,  vanilla extract and / or lemon zest and 4 tablespoons of potato starch and thicken over high heat moving so that no lumps are made