In small bowl, sprinkle yeast over warm water. Add sugar and let warm water. Add sugar and let stand until bubbly, 5 to 10 minutes.
Meanwhile, in food processor, process rolled oats until finely ground. On work surface, toss together the ground oats, 1 cup of flour and salt and form into a mound. Make a wide well in center.
In small bowl, lightly beat 3 of the eggs with fork. Stir in honey and butter. Pour egg mixture into the well and add yeast mixture.
Stirring with fingers of one hand, begin incorporating dry ingredients into liquid in the well. With pastry scraper in other hand, combine ingredients, forming dough into a ball. Scrape work surface clean and dust lightly with flour. Knead dough, dust lightly with flour. Knead dough, adding remaining 1/2 cup flour as necessary, 2 tablespoons at a time, until the dough is smooth and elastic, 7 to 10 minutes (you may have some flour left over).
Rinse out large bowl with warm water, transfer dough to the bowl and cover with plastic wrap. Let rise in warm place until doubled in bulk, about 1 hour.
Punch down dough. Turn out onto work surface and shape into thick loaf, about 15 inches long. Transfer to large ungreased baking sheet. Cover with towel and let rise until doubled in bulk, about 45 minutes.
Preheat oven to 375°. In small bow, beat remaining egg with 1 tablespoon of water. Gently brush egg glaze on risen loaf. Sprinkle poppy seeds on top, if desired, and bake for 35 minutes or until bread is deep golden brown. Transfer loaf to wire rack to cool completely before slicing.
Makes good French toast. This eggy yeast bread combines elements of Jewish challah and Italian semolina bread.