Combine first 8 ingredients in a food processor or blender, and process until smooth. Place pesto in a small nonstick skillet; cook over low heat until warm. Remove from heat; keep warm.
Heat 1 teaspoon olive oil in a large nonstick skillet over medium-high heat. Add the mushrooms and shallots, and sauté 4 minutes.
Combine penne, pesto, and mushroom mixture in a large bowl; toss gently.