Remove stems from portobello mushrooms.
Brush mushrooms, asparagus and tomatoes with olive oil. Grill mushrooms over medium heat until tender, 4 to 5 minutes per side, turning occasionally. Cut mushrooms into thin strips; place in a medium bowl.
Grill asparagus over medium heat for 3 to 4 minutes, turning occasionally. Cut asparagus into 2 inch lengths; add to mushrooms in bowl.
Grill tomatoes, cut side down, over medium heat for 3 minutes. Add to mushrooms and asparagus and toss in the pasta. Drizzle with lemon juice and olive oil. Sprinkle with seasoning, tossing gently to coat.
Combine all ingredients in a bowl and transfer to an airtight container. Store in a cool, dry place up to 6 months.