Add 1 Tablespoon sugar and yeast to warm water, stir well and "proof" the yeast (I'm old-fashioned and still do this). After the yeast proofs, add rest of the sugar, butter/margarine, 3 lightly beaten eggs, and five cups flour. As your stir together, add salt (done this way because salt can kill yeast if added directly). Beat ingredients with a spoon, gradually adding flour, until dough is stiff. Knead on board until dough is smooth and elastic (8-10 mins).
Cover and let rise in warm place -- until about doubled in size (1.5-2 hrs).
Punch down and knead dough until all the bubbles are gone. Divide into 6 parts, roll each part between your hands into a rope about 1" in diameter. Braid 3 ropes each into 2 loaves. Place two braids about 6" apart on a buttered/margarined cookie sheet, and allow to raise in a warm place until almost doubled in size. Brush tops with egg/water wash and sprinkle lightly with poppy seeds. Bake in pre-heated 400F oven for 35-40 mins, or until loaves sound hollow when tapped. Cool covered with a soft towel on racks.
Adapted from Beard on Bread by James Beard