Place a pot with water on to boil.
Meanwhile, heat olive oil in a large skillet over medium-high heat. Add onions and cook 5 minutes, stirring occasionally.
Add ground beef and break into small pieces. Add parsley, rosemary, thyme, salt and pepper and stir well. Cook for 5-6 minutes until meat is browned.
Add Worcestershire sauce and garlic. Cook for one minute. Add flour and tomato pasted and stir well.
Add broth and frozen veggies. Bring to a boil and them simmer for five minutes, stirring occasionally.
Set meat mixture aside. Preheat oven to 400 degrees.
Add potatoes to boiling water and cook until fork tender, about 10-12 minutes.
Drain potatoes well and return to hot pot. Add butter, milk, yogurt or sour cream. Mash and stir potatoes until mixed together. Add cheese and stir to combine.
Pour meat mixture into an 8"x12" baking dish. Spread evenly. Spoon mashed potatoes on top and spread evenly. Garnish with additional chopped parsley.
Bake uncovered for 20-25 minutes. Cool for 10 minutes before serving.