Preheat oven to 425°F (218°C). Heat 6 cups of water in a large pot; once boiling, add 1 tablespoon of sugar.
Once the bagels have risen and are puffy, boil them for 2 minutes per side, working in batches of 3–4 bagels at a time so the pot isn’t crowded.
Remove the bagels with a slotted spoon, then place them back on the parchment paper until cool enough to handle.