French Onion Soup Flatbread

In the bowl of a stand mixer fitted with the hook attachment (or a large bowl if kneading by hand), place 1 3/4 cups of the flour, the milk powder, sugar, yeast, salt and whisk together with a hand whisk or fork. Add in the oil and whisk together until throughly mixed.

With the mixer on low speed, gradually pour in the warm water. Knead together until a smooth and uniform dough starts to form.

If the dough is still very sticky, gradually add the rest of the flour, one tablespoon at a time until the dough clears the sides on the bowl but sticks to the bottom. You might not need all of it. Continue kneading until the dough is smooth and elastic but not dry. It should feel tacky and slightly sticky, but should leave your finger clean when you touch it. Resist the temptation to add too much flour or the crust will be tough.

Turn the dough on to a lightly oiled counter and knead a few times then shape into a ball (**see note for freezing dough after this step).

Transfer the dough to an oiled bowl, and turn it over to get it all covered with the oil. Cover with plastic wrap and place in a warm place (***see note for rising tip). Let it rise until doubled in bulk, 45 minutes to 1 hour. Meanwhile prepare the caramelized onions.

During the last 15 minutes of rising, place the oven rack to middle position. Preheat oven to the highest temperature, (mine is 260C/500F) with pizza stone inside. (If you don't have a pizza stone, use an upside down baking sheet. This helps create a beautiful golden brown bottom with a soft and chewy interior)

Combine onions and 1/2 teaspoon salt in a medium microwave-safe bowl and cover with large microwave-safe plate (plate should completely cover bowl and not rest on onions). Microwave on high power for 20 minutes until onions are soft and wilted, stirring halfway through cooking. (Use oven mitts to remove bowl from microwave and remove plate away from you to avoid steam burn.) Drain onions of any accumulated juices, if there are any.

Place a large skillet (preferably cast iron or sauté pan over medium-high heat and melt the butter. Add the wilted onions, and using a wooden spoon or spatula, cook onions, stirring frequently and scraping bottom and sides of skillet, while the liquid evaporates and onions start to brown, reducing heat to medium if onions are browning too quickly. Continue to cook, stirring frequently, until skillet bottom is coated with a dark crust, about 8 minutes, adjusting heat as necessary.

Scrape any fond that collects on the spoon back into onions. Stir in 2 tablespoons of beef broth, scraping skillet bottom to loosen the crust, and cook until broth evaporates and pot bottom has formed another dark crust, 2 to 3 minutes. Repeat this process of deglazing the skillet with broth 2 or 3 more times, until onions turn brown.

Stir in balsamic vinegar and cook, stirring frequently, until the vinegar evaporates, about 1 minute.

Taste the onions for sweetness. If it is not as sweet as you'd like, stir in 1 teaspoon of sugar, more or less according to your liking. Cook, coating the onions with the sugar until it turns a deeper shade of brown.

Taste again and adjust seasoning, adding more salt, sugar or balsamic vinegar to your preference.

In a small bowl, combine the butter and garlic.

Turn the risen dough onto a counter and cut in half.

Dust a large piece of parchment paper with flour and place one of the dough pieces on it. Flatten the dough with your fingers into an oblong shape, about 11"X5"/28cmX13cm.

Spread the garlic/butter mixture all over the flattened dough, then top with 1/2 cup of the shredded gruyere cheese. Add half the amount of caramelized onions, or less if you like (*****see note for storing leftovers) then top with 1/4 cup mozzarella cheese. Repeat with the other half of the dough.

Transfer the flatbreads into the HOT oven with the parchment paper and bake until the crust is golden brown, the cheese melts and bottom browns, 6 to 8 minutes.

Remove from the oven, sprinkle freshly grated parmesan cheese and thyme leaves on top of the flatbreads. Slices into sticks or wedges and serve while still hot.