Mix the yeast with the water in a small bowl and let stand until foamy, about 5 minutes.

Meanwhile, combine the flour, maple syrup, canola oil, maple sugar, salt, 2 of the whole eggs and the egg yolk in a large bowl. Add the yeast mixture to the bowl and stir with a wooden spoon until a shaggy dough forms about 2-3 minutes. (Alternatively, use a stand mixer fitted with the dough hook attachment.)

Turn the dough onto a lightly floured surface and knead until smooth and supple, 6 to 8 minutes. The dough can be slightly tacky, but not sticky. If the dough is sticky, lightly sprinkle 1 tablespoon of flour at a time and continue kneading until dough is no longer sticky.

Place the dough in a lightly oiled bowl and cover with a towel. Let sit in a warm place until it has doubled in size, approximately 2 hours.

Punch the dough down and divide into 4 equal pieces. Roll 3 of the 4 pieces into long ropes, about 2 feet in length, thicker at the center and thinner at both ends. Braid the 3 long ropes and tuck the ends under to seal. The braid should be about 14-inches in length.

Take the fourth piece of dough and divide it into 3 equal pieces. Roll these out in the same way to about 16-inches in length and braid. This smaller braid should be about 12-inches in length.

Place the smaller braid on top of the larger braid and gently press together to seal.

Preheat the oven to 350 degrees. Beat the remaining egg and brush the challah liberally with the egg wash. Sprinkle with the sesame seeds and let rise again until it has doubled in volume, about 30 minutes.

Bake, rotating halfway, until the challah is golden brown, about 30 minutes. Remove from the oven and let cool completely before slicing. Serve the same day.