Heat oven to 350 degrees F.
In a large bowl, toss the mushroom caps with enough olive oil to coat the caps. Add the rosemary, thyme, and garlic and combine thoroughly.
Place a roasting rack on a baking sheet. On the baking sheet, turn the mushroom caps upside down, stem side facing up. Roast the mushroom caps up to 10 minutes, or until the tip of a paring knife can be inserted into the side of the mushroom with little or no resistance.
Heat broiler to high and move the oven rack up 1 level. Mound 1 tablespoon of filling into each mushroom cap, avoiding overstuffing the caps. Top each cap with enough bread crumbs to cover the filling. Broil the mushroom caps on high for 3 to 4 minutes, or until the filling bubbles and the tops have browned.