My Cheese Puffs came out flat. No puff. The recipe called for 1 cup water, 1 bar butter, half teaspoon salt, 4 eggs, 1 cup flour, then cheese and herb. I heated the batter and stirred. It did not thicken like it did in the pictures. Added 3 TBS flour, but that didn't help much. Flat puffs are not cute. Anyone know what I did wrong?