In the bowl of a stand mixer fitted with paddle attachment, mix the sifted flours, the yeast,
grated Tonka bean and mix to combine.
Gradually add lightly beaten eggs and start to knead.
When the dough is formed, switch to dough hook and continue to knead.
Gradually add sugar, then butter, a piece at a time.
When the butter is well incorporated, add salt and continue mixing for about 10 minutes on medium speed, until dough is completely smooth, elastic, shiny, and pulls away from the sides of the bowl. During mixing, you will need to scrape down the sides of the bowl.
Shape the dough into a ball, place into a bowl, cover with plastic wrap and let rise until double in size.
On a floured surface, deflate the dough, shape into a ball, place into a bowl, cover with plastic wrap and refrigerate for 12 hours.
Roll out dough on a lightly floured surface and shape into a rectangle measuring 16x12 inches (40x30 cm) and brush the surface with melted butter.
Sprinkle chocolate chips and gently, pass the rolling pin on the surface so as to insert chocolate chips. Use both hands to roll up the rectangle like a roulade, starting from the long side
and ending at the other long end.
Cut one end, long about 1.8 inches (4,5 cm) and set aside.
Using a knife, gently cut the roll in half lengthwise, leaving the top uncut, for about 1.5 inches (4 cm).
Take the two pieces and loosely twist together, leaving the cut side up, place the cutted end inside and seal the dough.
Line with parchment paper a 9.5x4.3x3 inches loaf pan (24x11x7,5 cm).
Place the twist in the parchment-lined bread pan, let the loaf proof until doubled.
Brush with egg wash and bake for 26 minutes in a fan oven 340F - 170°C.
Let cool on a wire rack before serving.