Combine bread flour, instant dry yeast, salt, and sugar in a bowl and mix well.
Add lukewarm water and knead until the dough becomes smooth.
Let the dough rise for 1 hour.
Divide the dough into 2–3 pieces, shape them into balls, and make a hole in the center to form bagel shapes.
Add a little salt to boiling water and blanch the bagels for 30 seconds on each side.
Sprinkle coarse salt on top of the bagels.
Bake in a preheated oven at 180°C for 20 minutes.