Mix together the flour and semolina in the bowl of a stand mixer, or mix them up and create a mound on the counter top with a crater in the center. If using a stand mixer, add the eggs to the dough and mix them together with the paddle or dough hook until well mixed. On the counter top, crack the eggs into the center of the flour and semolina. Use your fingers to gradually draw the dry ingredients into the center, mixing them with the eggs. The dough will be hard to mix at first – a pastry scraper will help you draw it all together – but eventually it will come together and be relatively smooth.
Knead the dough with the heel of your hand for at least three minutes until the dough is very smooth. The dough should not feel sticky. If it sticks to your fingers, knead in a small amount of flour, just enough so your fingers come away clean when you pull them away. Wrap the dough and let it sit at room temperature for an hour.
(You can keep the dough for several hours at room temperature.)