Step 1Make the garlic croutons: Heat the oven to 350 degrees. Place the bread cubes on a baking sheet and bake until golden, 8 to 10 minutes. Put the croutons in a medium bowl and sprinkle with the rosemary and olive oil. (Leave the oven on.) Toss the croutons with the garlic; set aside.
Step 2Put the pine nuts on a small baking sheet and toast in the oven for 3 to 5 minutes, or until just golden. Don't overcook -- they burn easily. Pour them into a bowl and season with salt to taste. Set aside.
Step 3Clean the mushrooms by cutting away any rough spots and brushing away any dirt. Slice them into bite-size pieces, toss together in a bowl and set aside. Slice the prosciutto into thin 1-inch-long strips. Set aside.
Step 4Mince the shallot and place it in a small bowl. Add the vinegar, then drizzle in the hazelnut and walnut oils, whisking constantly. Stir in the chives, sage and pepper to taste.
Step 5Put the lettuces in a large salad bowl, add the basil and toss well.
Step 6Heat the olive oil in a large skillet over medium-high heat until almost smoking. Add the mushrooms, season with a pinch each of salt and pepper and toss well. Cook, stirring occasionally, until the mushrooms are turning golden, 5 minutes. Quickly add the vinaigrette, stir well and remove from the heat. Immediately add the mixture to the lettuces and toss once. Add the pine nuts, prosciutto and croutons (discarding any extra garlic and rosemary) and toss vigorously. Taste for seasoning, adding salt and pepper if needed and divide among eight plates. Serve quickly, before the lettuce can become soggy.