1 1/2 lbs. russet potatoes, peeled, quartered and rinsed
1/2 c. reserved cooking water from potatoes or milk
2 tbsp butter
Ground white pepper
3 tbsp. vegetable oil
1 onion, chopped
1/2 c. carrot, chopped
1/2 c. celery, chopped
1 lb. ground beef or turkey
1 Tbsp. flour
3/4 c. beef or vegetable stock
1 tsp. thyme
1 tsp. rosemary, crushed
Pinch of ground nutmeg
1/2. c frozen peas
2 tbsp butter
Put potatoes in a large pot, cover with cold water, and bring to a boil over medium-high heat. Cook until tender. Drain and mash, then add 1/2 cup reserved cooking water or milk, butter, and salt and pepper to taste and stir/mash until smooth. (I imagine you could also use store-bought mashed potatoes instead of making your own.)
While potatoes are cooking, heat oil in large skillet over medium-high heat. Add onion, carrots and celery; cook until softened. Add meat, cook until thoroughly done. Add flour; cook 2-3 minutes. Add stock, spices and peas. Reduce heat to low and cook until thickened, about 5 minutes. Place meat mixture in 9-in pie plate or 8 x 8 baking dish. Spread the mashed potatoes over the top. Cut the 2 T. of butter into small pieces and scatter across the top. Cover and freeze.
Take out of freezer and thaw in refrigerator 24-36 hours before you plan to eat. Preheat the over to 400. Bake for 30-35 minutes. Let cool slightly before serving.
Gluten-free adaption: Use gluten-free all-purpose flour in place of regular flour.
Dairy-free adaption: Use cooking water or unsweetened soy milk for potatoes. Use non-dairy butter in place of regular butter.