Preheat the oven to 180°C (350°F) and line a large baking sheet with parchment paper.
In a large mixing bowl, combine 1 cup nonfat Greek yogurt, 1 cup self-rising flour, and 1/4 teaspoon salt; stir until a thick dough forms.
Lightly flour a work surface and turn the dough out onto it; shape into a smooth ball with your hands.
Divide the dough into 8 equal portions for large bagels (or 12 for small). Roll each portion into a log, then join the ends to form a ring-shaped bagel.
Place the formed bagels on the prepared baking sheet. Brush the tops with melted light butter, if using, and sprinkle with 2 tablespoons sesame seeds or other desired toppings.
Bake for 15–20 minutes, until the bagels are golden brown on top. Remove from the oven and let cool completely before slicing and serving.