Stir the flour, yeast, and salt together in a large bowl. Add the warm water and olive oil, then mix until a dough forms.
Knead the dough on a lightly floured surface for 5 minutes until smooth. Cover and let it rest for 10 minutes.
Divide the dough into 12 equal pieces. Roll each piece into a rope and tie it into a knot. Place the knots on a parchment-lined baking sheet.
Bring the 6 cups of water and baking soda to a boil in a large pot. Drop in 3 or 4 knots at a time and boil for 30 seconds each. Remove with a slotted spoon and return to the baking sheet.
Whisk the egg white until frothy. Brush it over each knot, then sprinkle with black sesame seeds and flaky sea salt.
Bake at 425°F for 15 to 18 minutes until the knots turn deep golden and feel crisp.