Clean mushroom caps with a damp paper towel. Cut off stems from mushroom caps; rinse under cold water.
Coarsely chop stems and set aside. Use a spoon or paring knife to scrape out and discard gills from mushroom caps.
Brush 2 teaspoons of the oil over mushroom caps; place oiled sides down on a 15 x 10" jelly roll pan or baking sheet.
Heat remaining oil in a non-stick skillet over medium-high heat. Add asparagus, shallots, garlic and chopped mushroom stems. Cook 5 to 6 minutes or until vegetables are crisp-tender, stirring occasionally.
Remove from heat; stir in tomato, salt and pepper. Spoon mixture into mushroom caps. Combine bread crumbs and cheese; sprinkle evenly over mushrooms.
Bake 10 to 12 minutes or until hot and crumbs are golden brown.
Note: to make fresh bread crumbs, tear 1 to 2 slices multigrain bread into pieces and process in a food processor until coarse crumbs appear. Extra bread crumbs may be placed in a food storage freezer bag and frozen up to 3 months.
There are 218 calories in 1 serving of Asparagus Stuffed Portabello Mushrooms.