Dice onion[1] and set aside.  Next peel and cut the sweet potatoes into approximately 1 inch cubes.  Add cubes to pot of boiling water and cook until potatoes can be easily poked into with a fork.

While the sweet potatoes are cooking place bacon on a cookie sheet and bake at 400 degrees for approximately 18-20 minutes until crispy.

Add extra virgin olive oil to a frying pan and heat over medium.  Then add diced onion and saute until soft.  Finally place onions in large glass casserole dish.  Add frozen peas, carrots, and green beans to frying pan and cover.  When veggies are no longer frozen remove them and add to casserole dish with the onions along with finely chopped thyme and a couple pinches of salt and black pepper.  Mix all ingredients.

Brown the ground lamb in the same frying pan that was used for the veggies over medium heat.  Drain excess fat and layer in the casserole dish above the veggies.

Drain the sweet potatoes in a colander and then add to a food processor.  Next add minced garlic, pinch of salt, and optionally butter to the food processor and puree until consistency is smooth.  Using a spatula spread the pureed sweet potato on top of the ground lamb.

Chop the bacon and evenly sprinkle on the sweet potatoes.  Finally place the casserole dish in the oven for 10 minutes.

Optional: Finely chop fresh parsley and add directly before serving.

[1] http://www.youtube.com/watch?v=q_2TBbfMLzs