Dissolve yeast in 1/2 cup warm water. Sprinkle a dash of sugar on top to feed it. Set aside to proof.
Meanwhile, in a large bowl, add flour and make a well in the middle. On top of the flour, add sugar, salt, butter pieces and lemon zest.
After yeast is bubbly, pour into the well and sprinkle a little flour on top. Add beaten eggs to yeast in center. Using a wooden spoon, start stirring in the eggs, adding/pulling in a little bit of flour from the sides. When you can't stir it anymore, begin to add the warm milk and keep stirring and adding milk until it's impossible to stir.
Now, using your hands, keeping adding milk and blending in the flour until the dough is soft and barely tacky but not wet. You may or may not use all the milk (depends on the weather).
Turn out the dough onto a very lightly floured surface. Knead for about 10 to 15 minutes to develop the gluten properly. Dough should spring back quickly from touch. Put into a lightly oiled bowl, turn once and cover with plastic wrap (touching the dough) and a towel. Place in a warm area to rise for at least one hour (should double in bulk).
When fully risen, remove and divide dough in two. Set one aside under a warm towel. With the remaining piece, divide it into three equally-weighted pieces. Set two aside. Using a heavy rolling pin and your hands, begin to roll the dough into a rectangle. (Size doesn't matter, just so long as it isn't longer than a 1/2 sheet pan.) It should be very thin.
Using a pastry brush, coat the whole piece in melted butter. Liberally sprinkle on the cinnamon/sugar mixture and spread some raisins (if you want) over the whole piece. Carefully roll up the dough lengthwise. Pinch the seam together and place on 1/2 sheet pan that is lined with parchment paper. Cover with a warm towel. Repeat the process with the other two pieces of dough.
When all three are done, braid the "strands" loosely together. Cover with a clean towel and place in a warm place to rise again for at least 30 minutes.
Repeat the whole process with the other half of your dough batch.
Paint the braids with the egg wash and bake in a preheated 350 degree oven for approximately 25 to 35 minutes. Bread should be deep brown and slightly hollow when tapped.
Slide the bread on the paper off the pan onto a cooling rack and allow to cool to the touch. Remove paper.
If you want to pack it for a gift, allow it to cool completely. Then wrap tightly in good plastic wrap, then in foil. Cover with pretty cellophane and tie each end with curling ribbon.