Bring bread flour, cocoa powder, instant yeast, salt, sugar, milk and butter into the stand mixer bowl. Beat in medium high speed until a soft dough ball forms. Cover it with plastic wrap and let rest for 30 minutes. Divide the dough ball into six equal pieces. Roll into 6 dough balls. Cover with plastic wrap and let rest for 20 minutes. Roll each dough ball flat, add in some chocolate chips, roll it up and shape into a bagel. Cover them with plastic wrap and let rise until doubled in size.

Preheat the oven to 200℃(392℉). In a pot, put in 500g water, and 20g granulated sugar, heat until simmer, put in each bagel, cook for 20 seconds each side.

Line the baking tray with a baking mat or parchment paper. Send the bagels into the oven to bake for 18 minutes. Let the bagels cool down then serve.