Preheat oven to 350°F. Line a large baking sheet with parchment paper or silicone baking mat. In a large bowl, add yogurt and flour. When measuring out the yogurt, make sure that you strain out any liquid. Any extra liquid sitting in your yogurt will cause the dough to be too wet. Using a large spoon or spatula, mix together flour and yogurt until it begins to form a crumbly dough. Use your hands to push the dough together into one ball. The dough will be very sticky. Add your dough to a stand mixer with a dough hook attachment. Knead the dough until it comes together in one ball and has pulled away from the sides of the mixing bowl. As soon as it reaches this stage, it is ready and you should stop the mixer immediately. (You can view my video above for reference). If you continue to let it knead, the dough will actually become sticky again. If you do not have a stand mixer, you can knead the dough by hand. You will need to cover your kneading surface with flour and knead the dough by hand until it is tacky and no longer sticky. I prefer using the stand mixer because it is faster and the dough comes together without the extra flour which results in a lighter bagel. Divide dough into four equal balls. Roll out ball on a lightly floured surface until it becomes a rope about 3/4 inch thick. Try to make the rope as even and smooth as possible. Pinch ends shut to form a round circle. Repeat with remaining dough. Place bagels onto baking sheet. Brush tops with egg wash. Sprinkle tops with whichever seasonings you prefer. Bake bagels for about 23-25 minutes or until bagels are cooked all the way through. Remove bagels from the oven and turn heat up to 500°F. Place bagels back in oven and bake about 2-3 minutes until surface is browned. (If you are making plain bagels without toppings, you can also set your oven to low broil for 2-3 minutes to brown the bagels but I don't recommend this if you have toppings as the toppings will start to burn before the bagels finish browning.) Let bagels cool a few minutes before eating.