In a small bowl, combine egg white and 1 teaspoon water for egg wash and beat with a fork to loosen the egg white. Set aside.
Combine flour, baking powder, and salt in bowl and stir with whisk to combine.
Add yogurt to the bowl and mix well using a fork or pastry cutter, making sure the ingredients are well-combined.
Using your hands, gather dough into a ball. If it is too dry, add 1 teaspoon of water and mix again until it comes together.
On a lightly floured surface, knead the dough about 10 times and form into a slightly flattened ball.
Cut dough into 8 equal pieces.
Roll each piece into a log.
Shape log into a bagel, overlapping and squeezing the ends together well.
Transfer to parchment lined baking sheet. Repeat with remaining dough.
Brush bagels with egg wash, making sure to brush around all the edges.
Sprinkle toppings over bagels if desired.
Bake for 25 minutes on an upper rack.
Transfer to a cooling rack and let cool at least 15 minutes before slicing, preferably longer.
Store in a sealed bag for 1-2 days.
Notes
Full-fat Greek yogurt, low-fat Greek yogurt, or non-fat Greek yogurt all work with this recipe.
If you choose to use regular yogurt (not Greek yogurt), start with 1 cup first to see how the dough comes together as regular yogurt is much thinner than Greek yogurt. Add more regular yogurt, a bit at a time, mixing well after each addition, to achieve the proper dough consistency.
Please note that sometimes measuring flour by volume can vary depending on how loosely or packed the flour is in the cup.
If your dough is too sticky, add more flour, a little bit at a time, mixing well after each addition, until the dough comes together and you can handle it.
If your dough is to dry and not sticking together, add a little more yogurt, a tablespoon at a time, mixing well after each addition, until the dough starts to form.
This recipe makes 8 - 4" bagels. If you want to make larger bagels, cut the dough into 4 or 6 pieces instead of 8.
Be sure to brush the egg wash on all exposed sides of the bagels (including the inside edges!).
Bagels will keep for a couple days in a sealed bag.