Meanwhile, separate dough into 8 biscuits; shape each into a ball. With kitchen scissors, cut 1/2-inch-deep crisscross slashes on top of each biscuit, forming an X. Gradually stir 1 tablespoon of the baking soda into boiling water (water will foam slightly). Add two biscuits at a time to water for 15 seconds. Using tongs or slotted spoon, turn biscuits over; simmer an additional 15 seconds. Repeat with remaining biscuits, adding 1 tablespoon of the baking soda each time. Place biscuits 2 inches apart, top side up, on cookie sheet. Sprinkle with salt. Bake 15 to 22 minutes or until golden brown. Keep warm.