1. In a plate, mix mustard and flavouring.
2. Cut the tomatoes into half.
3. Preheat oven to 425 degrees Fahrenheit.
4. On a baking dish, place the tomatoes and spread mustard mixture over each.
5. In a bowl, mix rest of the ingredients and divide equally among tomato halves.
6. Place the dish in oven and bake for about 8 minutes until tomatoes are tender.
7. Serve Mustard Baked Tomatoes with just about anything that you like.