Direction :

1. Whisk one cup (128 g) of the flour with the yeast and stir in the lukewarm water until combined. Cover with plastic wrap or a dish towel and let rise about 45 minutes or until puffy and bubbly.
2. Directly into the bowl, add the salt, honey (or sugar), oil, eggs, zest and vanilla. Stir with a spatula or spoon until well mixed, then add the remaining four cups (486 g) of flour. Stir with a spoon until dough forms a sticky mass. Turn dough onto lightly floured work surface and knead for just a few minutes, until dough becomes smooth. Transfer to a lightly oiled bowl, cover it with dish towel or plastic wrap and let it rise in a warm spot until doubled in bulk, one to two hours or longer depending on the temperature of your kitchen. (To create a warm place to rise, see notes above.)
3. Make the filling: Melt butter and chocolate together until smooth — you can do this in the microwave at 30 second intervals or in a saucepan. Stir in powdered sugar and cocoa until smooth.
4. Punch down dough and divide into two equal parts, about 600 g each. Using a rolling pin, roll one half into a rectangle about 10- to 11-inches in width by 14- to 16-inches in length. Spread half of filling over top leaving ½-inch border all the way around. Starting from the short end, roll into a tight coil. To help keep coil bound, I wrap it in parchment paper and transfer it to a rimmed baking sheet. Repeat with remaining dough and filling. (Note: you can make the recipe up until this point and put it in the refrigerator overnight — this works really well).
5. If you are not refrigerating rolled dough overnight, transfer loaves to freezer to chill for 15 minutes — this was a Smitten Kitchen tip, which makes cutting and shaping the rolls easier. Meanwhile, coat two 9-by-4-inch loaf pans and one small vessel — I use a mini loaf pan — with butter.
6. Place logs onto a large cutting board and remove parchment paper. Line each loaf pan with the parchment paper, folding as needed to make it fit the pan. Trim last inch (or less) off each log. Cut the logs in half lengthwise and lay them next to each other cut sides up. Lift one half over the other and twist each around the other — see photos for guidance. Transfer the twist as best as you can into the prepared loaf pan. Repeat with remaining two halves. Nestle trimmed ends into small vessel. Cover pans with plastic wrap and let rise 1 to 1½ hours at room temperature or until dough has risen and is filling the pan.
7. Heat oven to 375°F. Remove plastic wrap, place loaf pans on a sheetpan and bake on the middle rack of your oven. Bake for 25 to 30 minutes. Check the mini pan around 20 minutes — it will be done before the others. If the loaves are browning too quickly, cover them with foil.
8. While babkas are baking, make syrup: Place orange juice/water and sugar in a small saucepan and bring to a simmer until sugar dissolves. Remove from heat and set aside. Remove babkas from oven, brush some of the syrup over the small pan, then pour half of the remaining syrup evenly over each of the loaves. Let loaves cool completely in loaf pan if you are able to refrain, otherwise 15 minutes or so should do it.