Cook pasta according to package directions.
Place mushrooms in 13x9-inch glass dish.
Whisk together oil, lemon juice, garlic, mustard, salt and pepper.
Pour over mushrooms; marinate 10 minutes.
Heat large nonstick skillet over medium-high heat.
Add half of mushrooms in single layer.
Cook 4 minutes on both sides or until mushrooms begin to brown.
Place pasta on serving platter.
Top with mushrooms; cover.
Repeat with remaining mushrooms and add to pasta; top with blue cheese.