In the bowl of a stand mixer, dissolve the yeast and honey in the lukewarm water. Let stand for 10–15 minutes, until frothy.

Attach the dough hook. Add the flour, salt, three beaten eggs, and oil. Mix on low speed for 2 minutes, until a shaggy dough forms, then increase to high speed and knead for 7-10 minutes.

Transfer the dough to a lightly floured surface and knead a few times, until smooth and elastic. If the dough is too sticky, add a little more flour.

Lightly oil a bowl and coat the dough with a thin layer of oil. Cover the bowl and let rise in a warm place for 1½–2 hours, or until doubled in size. Alternatively, refrigerate the dough overnight for a slow rise.

Punch down the dough and divide it into 6 equally sized pieces. Roll each portion into a tight ball. Cover the balls lightly with plastic wrap and let them rest for 10 minutes. 

Working with the first dough ball, roll it out on a lightly oiled surface into an 11x8-inch rectangle. Starting from the long side, roll the dough tightly into a log. This will create tension and layers, helping the challah bake high and plump. Set aside and cover with plastic wrap. Repeat with the remaining dough balls to form six logs.

Working with the first log, roll it with your hands from the center outward into a 16–18-inch strand. For a plumper challah, keep the center slightly thicker and taper the ends.

Braid three strands together to form one 3-strand challah. Repeat with the remaining three strands to make a second loaf.

Place the braided loaves on a parchment-lined baking sheet. Cover loosely with plastic wrap and let rise for about 1 hour, or until doubled in size. 

Preheat the oven to 350°F. Beat 1 egg with a splash of water and brush over the loaves. After 5–10 minutes, brush on a second layer of egg wash and sprinkle with seeds (if using). Bake for 35–40 minutes, until golden brown and hollow-sounding when tapped.

Cool on a wire rack and serve.