Portobello and Gruyere Canapes

In small bowl whisk together oil, vinegar and thyme. Brush both sides of mushrooms with oil mixture. In large nonstick frypan cook mushrooms over medium-high heat until tender, turning once. Remove from frypan.

In same frypan cook onion over medium heat until beginning to brown, stirring frequently.

Cut mushrooms into 1 1/2-inch pieces. Top each cracker with mushroom piece, some onion and some cheese. Place on baking sheet. Broil 4- to 5-inches from heat about 1 minute or until cheese melts.