Use flatbread and ricotta as a blank canvas, and show off the treasures from your garden or local farmers' market.
In the bowl of an electric mixer, combine the warm water, yeast, and sugar. Let stand until foamy, about 10 minutes.
Using the dough-hook attachment, slowly beat in flour, 1/2 cup at a time, until dough is tacky, but not sticky. Add salt; mix until combined. Add butter a few pieces at a time, beating on low speed until incorporated. Continue beating until smooth, 7 to 10 minutes. Transfer to a large oiled bowl. Cover with oiled plastic wrap; let rise in a warm place until doubled in bulk, about 2 hours.
Preheat oven to 500 degrees. If using, heat a pizza stone or tile on lower rack, 20 minutes. Punch down dough. Divide into six equal pieces. Place one piece on a clean surface; cover others with a clean kitchen towel while you work.
Gently pull and stretch dough into an 11-by-5-inch rectangle. Spread with 1/2 cup ricotta. Add desired toppings, and season with salt and pepper. Repeat with remaining dough and toppings.
Sprinkle a pizza peel or inverted baking sheet with cornmeal. Place tarts on peel, and slide onto heated stone or place baking sheet in oven. Bake until crust is golden brown, 10 to 12 minutes.
Drizzle baked tarts with oil, if desired, and serve warm or at room temperature.
Dough may be frozen, wrapped in plastic, for up to 1 month.
For toppings, we like tomatoes with fontina cheese and basil. We also like sliced yellow squash and zucchini, grated Parmesan cheese, and oregano; garnish with squash blossoms.