In a medium-size sauté pan over medium-high heat, melt butter. Add oil. Add onions and cook gently, stirring often, until lightly browned and sweet, about 20 minutes. Set aside.
Fill a medium-size saucepan with salted water and bring to a boil. Add asparagus and boil about 3 minutes. Remove from water and immediately place in a bowl of ice water. Once cooled, remove, drain, and pat dry.
Heat your grill to medium-high, and oil the grates lightly. Roll dough out as thinly as possible. Place dough on grates and cook about 1 minute, or until very lightly browned. Turn dough over and quickly spread a thin layer of sautéed onions over dough. Place asparagus over onions and spoon ricotta on top, in small dots.
Cover the grill with the lid. Let cook about 2 minutes and check; edges should be browned. Cook longer if necessary.
Transfer to a cutting board. Drizzle with olive oil and drape prosciutto over the top. Cut and serve.
In a standing mixer with dough hook, combine whole-wheat flour, all-purpose flour, yeast, salt, and sugar. With the motor running, gradually add oil and water. Knead on low speed until dough is firm and smooth, about 10 minutes.
Divide dough into four balls. Line two cookie sheets with parchment paper. Place two balls on a sheet and cover with a damp towel. Let them rise in a warm spot until they have doubled in bulk, about 2 hours.