Combine bread flour, all-purpose flour, kosher salt, sugar, instant yeast, and baking soda in a mixing bowl.

Form the mixture into a dough and knead until smooth.

Allow the dough to rise until doubled in size.

Divide the dough into equal portions and shape them into bagels.

Boil the bagels in salted water for a few minutes.

Bake the bagels on prepared baking sheets until golden brown.

Top with optional toppings as desired.