Preheat your oven to 400°F and line a large baking sheet with parchment paper.
In a large bowl, sift together the flour, salt, and baking powder. Add in the Greek yogurt to the dry ingredients and mix until thick and crumbly dough starts to form.
Flour your work surface generously to prevent sticking. Transfer the dough onto the floured surface and knead for a few minutes. If the dough is too sticky, sprinkle a little more flour onto the dough.
Once the dough is ready, divide it into 4 equal-sized portions. Roll each portion into a round ball.
To shape the bagels, use your fingers to create a hole in the center of each dough ball, gently stretching it out to form a ring. Work your fingers around the hole, expanding it until it is about 2-3 inches in diameter. Keep in mind, the hole should not be too large—just enough to create the classic bagel shape while leaving a fluffy, round center.
Repeat this process for all the dough balls.
Place the shaped bagels on the prepared baking sheet, spacing them about 1-2 inches apart to allow room for expansion.
With a pastry brush, brush each bagel with the whisked egg, coating all the bagels.
If desired, sprinkle your favorite toppings—such as sesame seeds, poppy seeds, or everything bagel seasoning—on top of each bagel.
Bake at 400℉ for 20-25 minutes, or until they are golden brown and cooked through. Once baked, remove the bagels from the oven and allow them to cool for about 5-10 minutes.
Serve the bagels warm or at room temperature, plain or with your favorite spreads and toppings.