Chop onion and herbs, if using fresh herbs.
Combine all but biscuit mix and milk in medium to large casserole.
Bake casserole at 425 for about 30 min or until Bubbly.
While mixture is baking combine biscuit mix and milk to make a batter.
*CAUTION: Do this as close to the 30 min mark as possible so batter does not prematurely rise.
When mixture is bubbly remove from oven and drop biscuit batter, by tablespoons, on top of mixture.
Return to oven and bake an additional 20-25 min.