We make this bread all the time, especially when we have guests. The dough is the one I use for my everyday breads, sometimes adding yogurt if I have leftover that is going too sour or any kind of mashed vegetables or greens. In the summer I use a tomato-onion-olive oil mixture, the leftovers from our daily tomato salad, pulsed in the blender, to make my Tomato Salad Bread which can also be topped with cheese and tomato slices. 
See also the Smoked Cheese and Kumquat Bread which is basically the winter version of my topped breads. For a more spicy-aromatic topping spread Zaatar mixed with olive oil over the tomatoes.
Yields 2 laganes (focaccia-like flat breads), each serving 6-8 people as appetizer
2 cups fine semolina or pasta flour
3 cups all purpose flour
1 1/2 cups whole wheat flour
1 cup barley flour (optional) or 1 more cup whole wheat flour
2 teaspoons instant dry yeast
2 teaspoons salt
3 1/2 teaspoons mixed ground coriander seeds, caraway and mahlep (optional)
1/2 teaspoon ground white pepper (optional)
About 3 1/2 cups spring water (preferably non chlorinated), or more, as needed
3 cups coarsely grated or shaved Metsovone, or aged smoked cheddar cheese
2-3 large beefsteak tomatoes, thinly sliced (as needed)
2 tablespoons or more rosemary leaves
About 4 tablespoons olive oil
Finishing salt and Aleppo pepper, or freshly ground black pepper, to taste (optional)
Place flours, yeast and spices in the bowl of a standing mixer and toss with a spatula. Make a well in the center and pour in the 2 cups of water.
Fit the bowl to the mixer and work with the dough hook on low for 1 minute. With the motor running add water as needed and work the dough for 5 minutes or more, occasionally stopping to turn over the dough with a large spatula. The dough should still be wet and somewhat sticky, but should start to come off the sides of the bowl. If too dry, add a little more water, if too wet add a few tablespoons of all purpose flour.
Lightly oil a large transparent or semi-transparent bowl, as well as a piece of plastic wrap. Turn out the dough onto a lightly floured surface and shape into a ball. Transfer to the oiled bowl. Cover with the oiled plastic wrap and let rise until double its original volume: about 1 hour or more.
(When the dough has expanded to about 1 1/2 times its size you may transfer the bowl with the dough to the refrigerator, and leave it overnight and up to 24 hours. It will continue to rise slowly. Before proceeding further, bring to room temperature).
Turn the dough out onto a lightly floured surface and halve with a spatula.
Line 2 baking sheets with parchment paper and place one piece of dough on each. Wet your fingers and push the dough making dimples with wet fingers, expanding it to fill the baking sheet. Cover with oiled plastic wraps and let the laganes rise for another 30 minutes –they won’t rise much.
Preheat the oven to 450°F (240° C).
Spread most of the cheese (keep 3-4 tablespoons) over each of the breads pushing and making dimples again, then arrange the tomato slices and top of the cheese, to almost cover the surface. Sprinkle with the rest of the cheese and the rosemary, and drizzle lightly with olive oil. If you like, sprinkle with some finishing salt and pepper.
Turn on the broiler and place the first baking sheet 5-6 inches from the broiler. Bake for about 5 minutes, until the cheese melts. Move the bread to the bottom of the oven, and slide the other baking sheet to its place. After another 5 minutes, turn off the broiler and lower the heat to 375°F.
Transfer the second bread closer to the bottom of the oven, bellow the first, and continue baking for another 15 minutes, changing once more the positions of the breads –always at the lower part of the oven. Check that both breads are well browned on top and bottom, or bake them a bit longer. When done, transfer to a rack to cool for about 10 minutes, before slicing to serve.
VARIATIONS:
Spread Zaatar mixed with olive oil over the tomatoes for a more spicy-aromatic topping. Instead of the basic dough, you could use the Tomato Salad Bread as base for this appetizer, one of the most popular among our friends and Kea Artisanal guests.
