In a large bowl whisk together salt, flour (start with 2 cups add a little more at a time up to 1/4 if needed), sugar and baking powder, make a well in the centre and add egg, egg yolk and butter (cubed), mix together (you can also use a food processor, pulse until dough just starts to come together), remove dough to a lightly floured flat surface and knead until it becomes a soft dough, wrap in plastic and refrigerate for 30 minutes.
In a medium pot, heat over low the milk, cream and lemon rind, until very hot but do not boil. Remove from heat and let cool to warm.
In a medium pot add yolks and sugar, whisk together until combined, then add flour and vanilla, place pot over low heat, pour the warm milk/cream through a sieve to remove the lemon rind (disgard), whisk continuously until thickened. Remove to a glass bowl, cover with plastic wrap (make sure wrap touches the cream mixture and refrigerate approximately 1 hour or until thickened.
Pre-heat oven to 350° (180° celsius) Grease and flour 6-9 medium and 6 small muffin tins.
Remove dough from fridge, on a lightly floured surface knead a few times to soften it up. Roll to 1/8" thickness, cut out circles and fit to muffin pan. Prick the bottom of the tart with the end of a fork and then fill almost to the top with Pastry Cream, top with another cut out circle, cut with a knife to remove excess dough and seal with fingers. (seals better with fingers lightly dipped in water). When complete, in a small bowl mix together 1 egg and 3 teaspoons cream, brush the top of each muffin tart and bake for approximately 30-40 minutes. Let cool to warm. Dust with icing/powdered sugar. Enjoy!