Disclaimer: I have never made this before, have only eaten it a few times from Cecil's in Saint Paul, and am not Jewish. This is a mashup of online reipes based on what I had available and what sounded good. Mostly I just post this so i can quick find how i made it for next time.
The Filling: 1cup Poppy seeds with one cup boiling water. let cool and then grind in coffee grinder. add 1cup milk. 3/4 cup honey. splash of lemon juice. Heat till it thickens. Let cool and then add an egg.
The Pastry: 2cup self rise flour. (or regular flour plus some baking soda) 1tsp salt 1 cup sugar (mix) Cut in 1 stick butter with a pastry cutter Mix one egg with 1tsp vanilla extract. Add the egg vanilla mix to the flour and work it until it is dough. You may need a splash of milk.
Assembly: Roll out and then cut with a big coffee mug. Add a big spoonfull of filling and fold up the three sides as shown below. bake at 375 for 20 min.