For the babka: Whisk the sugar, yeast and 1 cup of the warm water in a medium bowl. Set aside to bloom.
Add the bread flour to the bowl of a stand mixer fitted with the hook attachment. Make a well in the center of the flour and bury the salt in the well. Add the canola oil, honey, whole egg, remaining 1 1/3 cups warm water and the bloomed yeast, making sure no sediment is left behind. Mix on low speed for 30 seconds, increase to medium speed for 30 seconds and then increase to high speed for 3 minutes, mixing until the dough appears smooth.
Spray a large bowl with nonstick cooking spray and transfer the dough to the bowl. Cover with a damp towel or plastic wrap and set in a warm area to proof until doubled in size, about 1 hour.
Spray two 9-inch round foil cake pans with nonstick spray.
Turn the dough out onto a lightly floured surface. Split the dough into 2 loaves. Divide each loaf into 6 strands and roll each strand to elongate. Press 1 heaping tablespoon of chocolate chips into the center of each strand, arranging the chips in a line down the strand and then folding the dough around the chips to cover. Tie each strand into a knot and place 6 knots into each greased pan: one in the center, surround by five. Make sure that the knots are evenly spaced and not overlapping (they can still touch), leaving space to rise.
Whisk together the egg yolk with a pinch of salt and a pinch of sugar. Brush this egg wash over the shaped loaves. Let the loaves rise in a warm place until doubled in size, about 30 minutes.
Preheat the oven to 350 degrees F.
For the crunch topping: Mix the sugar and butter together in a medium bowl using clean hands. Add the all-purpose flour, mixing it in with your hands.
Sprinkle each loaf with 1 to 2 tablespoons chocolate chips and the desired amount of crunch topping. Bake until the topping is lightly golden brown, about 35 minutes. Transfer to a rack to cool.
To freeze, cool completely before transferring to a ziptop bag.