Put the water, sugar, yeast, flour and fine salt into the bowl of a mixer fitted with the dough hook attachment. Mix on low speed for 5-6 minutes to form a stiff, elastic dough. If the dough is too stiff to come together in a mass, add up to 1/4 cup of extra water, a tablespoon at a time, until the dough is smooth rather than shaggy. This step can be done by hand; bring the ingredients together in a large bowl, then knead on a clean counter for 8-10 minutes.

Set the dough to do its first rise, putting the bowl into the oven (uncovered). The dough should double in size during this step.

Remove the proofed dough from the oven and turn it onto a lightly floured surface. Gently knock back to remove any large air pockets, then divide it into 8 equal pieces. Form each dough portion into a smooth ball, then poke a hole through the center of each. Stretch and pull the dough to make the diameter of the holes about 1 1/2 inches. Place the bagels onto a parchment-lined pan (you will need to use 2 pans to fit all the bagels).

Put the formed bagels into the preheated oven and steam to set their shape and cook the outside of the dough.

Remove the steamed bagels from the oven and season while you preheat for the baking stage.

Mix together the seeds, garlic, onion and salt in a shallow bowl and set aside. In another shallow bowl, whisk the egg white with a tablespoon of water. Brush a little egg wash onto the top of each bagel, then dip it into the bowl of seasoning before returning to the pans.

Put the seasoned bagels back into the oven and cook until they're glossy and golden. You may need to switch the pans around halfway through baking to ensure they color evenly.

Remove the pans from the oven and transfer the bagels to a cooling rack. Allow to cool and serve at room temperature. Bagels will keep in a paper bag at room temperature for a day or two, or can be wrapped and frozen for up to 2 months.