01 - Combine bread flour, instant yeast, sea salt, and granulated sugar in a large mixing bowl. Mix thoroughly to distribute ingredients evenly.
02 - Add warm water and olive oil to the dry mixture. Stir until a shaggy, rough dough begins to form.
03 - Knead by hand on a floured surface or use a stand mixer with dough hook attachment for 5–7 minutes until smooth, elastic, and fully developed.
04 - Gently fold in chopped spinach and drained cottage cheese, kneading just until evenly distributed throughout the dough. The dough will feel slightly tacky due to the cheese moisture.
05 - Place dough in a lightly oiled bowl, cover with plastic wrap or a damp towel, and let rise in a warm, draft-free area for 1 hour until doubled in volume.
06 - Preheat oven to 425°F and line a baking sheet with parchment paper.
07 - Turn risen dough onto a lightly floured surface. Divide into 8 equal portions, approximately 4 ounces each.
08 - Form each portion into a smooth ball, then flatten to 1/2-inch thickness. Press your thumb through the center and gently stretch to create a 4-inch flattened ring with an even hole.
09 - Arrange shaped flagels on the prepared baking sheet, cover with a clean towel, and let rest at room temperature for 15 minutes to relax the gluten.
10 - Brush the tops of each flagel generously with beaten egg wash. Sprinkle sesame or poppy seeds evenly over the surface if desired.
11 - Bake for 18–20 minutes until deep golden brown with a firm, hollow-sounding crust when tapped on the bottom.
12 - Transfer flagels to a wire cooling rack and let cool for at least 30 minutes before slicing or serving to ensure proper texture set.