In lge. mixing bowl, combine half cup of the warm water, the yeast and sugar and let work til foamy. Mix remaining 1.5 c. warm water, salt, gluten flour, and A/P flour into the yeast mixture. Knead vigorously on a floured surface until smooth (dough will be soft). Form into ball and place in greased bowl andturn greased side up. Let rise, covered with plastic, until tripled in bulk, abt 90 min. Punch dough down, turn over, and let rise again til doubled. Punch down and roll into 2 cylinders. Cut each into 8 rounds, lay them flat, cover with a towel, an let rest. Meanwhile, prepare the topping by mixint oil, poppy seeds, onion and salt; set aside Pat dough into flattened rounds a little higher in the middle than at the edge, each abt. 9 cm in dia. Place on lightly floured board, cover with dry towel then damp one and let rise until half-proofed--abt. 30 min. Press bottom of shot glass or small jar abt 3 cm in dia. in center of each bialy to make deep indentation. Spread topping over the bialys. Let proof 15 min. more. 0.75 proof. Carefully transfer each bialy onto 2 lge. ungreased baking sheets. Bake on the upper and lower shelves of the oven for 6 to 7 min., then switch pans and turn front to back for even browning. Bake abt. 5 to 6 min more. Cool on racks. Store in plastic bags in 'fridge up to 2 days. Freeze for longer storage.