Heat oven to 350°F.
Stir sour cream, mustard powder, herbs, and thyme in a large bowl.
Add cheese and cup chopped basil.
Spread mixture into small pan or pie dish.
Sprinkle diced tomatoes on top of mixture.
Bake for 10 to 15 minutes or until cheese has melted and is bubbling.
While the dip is in the oven, slice the bread and place on a baking dish. Slightly drizzle or spray bread with olive oil.
Slide into the oven and bake 6 to 8 minutes until toasted.
After cheese is melted and bubbly, switch to broil and let it get extra crispy for about 5 minutes (watch closely).
Serve warm with the toasted bread.