1. Microwave butter in glass dish for 30 to 45 seconds, on HIGH, or until melted.
2. Preheat microwave browning grill for 5 minutes on HIGH. Cut each tomato into 3 slices; trim end slices so they will lie flat on grill.
3. Dip tomato in melted butter; coat with crushed croutons. Place on preheated grill.
4. Microwave for 1 minute on HIGH. Turn slices over and continue cooking for 1 to 1 1/2 minutes, on HIGH, or until tomatoes are heated.