Bialy Babka with Gouda Cheese

Servings 9 pieces

To make the filling, dice onion. Heat butter in a large pan and add in diced onion. Sauté and let it cook for 15-20 minutes in low medium heat. Stir every few minutes
Add salt and poppy seed when the onion is almost caramelized or until golden brown and very tender. Scoop out onto a plate or tray to let it cool.

To make dough, add in melted butter into a mixing bowl. Followed by milk, sugar and instant yeast.
Add in flour. You can use only all purpose flour or half mixed with bread flour.
Add salt, egg and egg yolk. Knead using a dough hook for 10-12 minutes. It will come together into a rich yellow hue and it will not stick on the bowl.
Turn out onto a clean surface a shape into a round ball by tucking the dough. Put back into the bowl and cover with a damp cloth. Leave it somewhere warm for about 1 hour and let it proof to double in size.
After 1 hour, punch dough to degas, turn out onto a clean surface. Roll into a smooth round ball again. You may leave it covered for 5 minutes or you don't have to.

Flip the dough so the smooth side is now facing the bottom. Use a rolling pin and roll out into a rectangle of 13-14" x 10", about 1-1.5cm thick. A tip to get it rectangle is to roll out diagonally to the edges, from the center. If the dough feels tight to roll out, you may leave it covered with a cloth for 2-3 minutes to let the gluten relax.
Spread cooled onion evenly. Grate gouda cheese if you want to add cheese. You can use emmental or other swiss cheese.
Roll into a swiss roll tightly. Put it on a tray and into the freezer for 5-10 minutes. Prepare the baking tin, spray a cooking spray or butter and layer a piece of parchment paper at the bottom and all 4 sides.
Remove from freezer, cut the log in half lengthwise. With both cut part facing up, lift the left side and layer it on top of the right, repeat to create a braid. Push both ends to the center to fit it into the baking tin. Don't worry if it looks squishy or messy. It will turn out beautiful anyway.
Cover with a damp cloth and let it proof again for 30 minutes.
Preheat oven to 170C about 15 minutes in. When dough is ready, grate more cheese on top
Bake at 170C for 35-40 minutes. If you cooked the onion to caramelized, you may want to cover the top with a piece of aluminium foil at the last 15 minutes so it doesn't burn the onion and you end up with bitter onion.
When it's done, remove from oven. You can remove from the pan while its hot or let it cool in the baking pan. Cut to slices to serve.