Heat the butter and 1 tablespoon of olive oil in a medium-sized sauté pan. When the butter has melted, add the onions and sugar. Cook slowly until the onions are soft and caramelized.
Heat 2 tablespoons of olive oil over high heat in a large sauté pan, then add the mushrooms. Sauté until the mushrooms turn golden brown and have cooked down.
Season with salt and pepper to taste.
Preheat the grill. Flatten the dough, brush with olive oil, and place the dough on the grill. Grill the flatbread dough on one side until golden brown, then turn over.
Spread with mozzarella, onions, mushrooms and blue cheese. Serve hot.
1 package dry active yeast
1 ¼ cups warm water
2 ¾ cups unbleached all-purpose flour, plus more flour for rolling the dough out
¼ cup whole wheat flour
2 teaspoons sea salt
2 teaspoons crushed fennel
extra virgin olive oil, for brushing the bread
Combine the yeast and water in a mixing bowl and let it rest until it becomes bubbly. This should take about 15 minutes.
Using the paddle attachment of your electric mixer, combine the flours into the yeast mixture. Add the salt and fennel.
Place the dough hook onto the mixer and knead for 5 to 7 minutes. Remove the dough. Place it in a lightly oiled bowl, turning the dough to coat it with oil on all sides. Cover the dough with plastic and allow it to rise until doubled in size, which should take about one hour.
Punch the dough down. Cover. Allow it to rise another time until doubled, which should take about 45 minutes.
Turn the dough out onto a work surface. Divide it into as many pieces as you need for whatever you're cooking. Brush lightly with olive oil. Cook on top of a hot charcoal grill or a stove top grill.