Steps

• For the microwave method: beat the egg with the sugar, add the cornstarch and then the milk. Cook at 800 watts for 4 minutes; after this time, take the bowl out and stir vigorously. Put the bowl back into the microwave at 800 watts for another 3 minutes.

  For the traditional method: in a bowl mix the egg and the sugar, also add the cornstarch. Meanwhile bring the milk almost to a boil and start pouring it into the bowl with the other ingredients. Pour the whole mixture into a saucepan and cook until it thickens.

  Once cooked, pour the pastry cream into a wide, cold container and sprinkle the surface with some granulated sugar to prevent a skin from forming. In an article: Food Wrap: How and When to Use It I explain why I do not use cling film in direct contact with the cream.

• With a fork work the eggs with the sugar, add the oil and mix. Add the cocoa and the baking powder, then start adding the flour in several additions.
  The dough should be soft, not sticky and compact; if necessary, add a little more flour. Roll the dough between two sheets of baking paper.

  

• Place the rolled dough inside a pan lined with parchment paper or greased and floured. Put the now-cold cream inside and level it; for the topping I decided to create shapes, but if you prefer you can make the classic lattice strips or, with the leftover dough, make cookies.
  Bake the tart at 356°F in a preheated conventional (static) oven for 30 minutes.

  

• Let the tart cool completely inside the pan.

  Thank you for cooking with me. See you on the next kitchen adventure and thank you always for the trust you’ve shown me all these years.