Make the dough: place the flour, yeast and sugar into the bowl of a stand mixer fitted with a dough hook attachment. Mix at a low speed for a few seconds to combine everything. Add the egg and water and mix on low speed for about 2 minutes until combined. Add the oil, lemon zest (if using) and salt and mix on medium speed until a smooth dough comes together, about 6-9 minutes. Use your hands to form the dough into a ball and place the dough into a large greased mixing bowl. Cover the bowl and set aside in a warm place for about 1 hour. The dough will puff up a bit after one hour but it will not rise significantly. 

In the meanwhile make the filling: place the ground poppy seeds, sugar and lemon zest into a bowl. Stir to combine. Pour the boiling water into the bowl and mix until the sugar dissolves and the poppyseed filling is a thick paste like consistency. Add more boiling water by the teaspoon if necessary. 

Preheat the oven to 375 degrees. 

Make the egg wash: Place the egg yolks into a small bowl and whisk well with the honey.  

Once the dough has proofed, transfer it onto a lightly floured surface. Roll out the dough into a large circle that is about ¼ inch thick.  Use a 3 inch round cookie cutter or glass cup to cut as many circles as you can into the dough. Pull the dough scraps off of the dough and set aside. Place about 1 teaspoon of the poppy seed filling into the center of each circle of dough. Brush the edges of the circles with a bit of water. Roll up 3 edges of the circle to form a triangular shape and pinch the edges together to seal the cookies. Use the dough scraps to roll, fill and shape more hamantaschen. Transfer the cookies onto a few parchment lined baking sheets, leaving about 2 inches of space between each cookie. Brush the tops of the cookies with egg wash.

Transfer the cookies into the oven and bake for 10-15 minutes or until the cookies are baked and golden brown. 

Let the cookies cool until they are at room temperature, about 30 minutes, and serve.