To make these bagels, start by preheating your oven to 375 F.
Next, prepare the bagel dough. In a large bowl or stand mixer bowl (which I recommend), mix together the flour, baking powder, and kosher salt until just combined.
Then, add in the yogurt and mix again, until the ingredients come together and a dough forms. The dough should be slightly sticky but not too sticky - if it is, you can add in more flour.
Next, divide the dough into four or eight, evenly-sized balls - four if making larger bagels, and eight if making smaller-sized ones.
Then, poke a hole in the center of each ball and roll them into bagels.
If using the egg, crack the egg into a bow, whisk it together, then use a pastry brush to brush the tops of each bagel.
Then, sprinkle the Everything But the Bagel seasoning on top of each bagel, if using.
Transfer the bagels into the oven and allow them to bake for 25-30 minutes, until they're golden brown. Be sure to rotate the tray halfway through, so that the bagels cook evenly.
Once the bagels are done, remove them from the oven. Allow them to cool for 15 minutes, then slice and enjoy!