Brush both sides of each slice of bread with 1/3 cup oil. Toast until lightly browned, 5 to 7 minutes. Let cool. (The crostini can be made up to 2 days ahead. Keep in an airtight container.)
Place asparagus stalks on a baking sheet and drizzle with remaining 1 tablespoon oil. Sprinkle with salt and pepper. Roast until the asparagus is just beginning to turn brown and crisp-tender, about 5 minutes. Let sit until cool enough to handle. Cut the asparagus crosswise into 1/4-inch slices. Set aside.
In a small bowl, mix together Ricotta, 1/2 cup Parmesan and 2 tablespoons basil. Set aside. (This can be made 1 day ahead. Cover and refrigerate.)
To make Parmesan crisps: Line a baking sheet with parchment paper. Place a heaping teaspoonful of Parmesan on the baking sheet. Smooth into a rectangle about the length of each crostini. Repeat with remaining Parmesan, spacing about 1/2-inch apart. Cook for 6 to 8 minutes or until golden brown. Let cool. (Parmesan crisps can be made 1 day ahead and stored in an airtight container.)
In a medium sauté pan, place the pancetta over medium heat. Cook until pancetta is crisp and brown around the edges, about 6 minutes. Remove to a paper towel-lined plate to drain. Let cool.
Spread about 1 teaspoon of Ricotta-Parmesan mixture on each crostini. Lightly press 5 or 6 slices of asparagus and 3 or 4 pieces of pancetta into the cheese mixture. Bake 7 to 9 minutes, or until the cheese is heated through and the edges of the asparagus are a shade darker. Remove from the oven and let cool 5 minutes. Place a Parmesan crisp on top of each crostini, sprinkle with remaining basil and serve.