Boil potatoes until tender. Mash potatoes with butter and milk. Add salt and pepper to taste.
Meanwhile, brown the meat and onions. Salt, pepper, and garlic to taste. Add carrots once meat is browned and cook for an additional 5 minutes, stirring often.
Add peas once carrots are softened.
Fit 1 pie crust into a deep dish pie pan, or casserole dish (omit for Whole 30 or GF).
Spread meat into a 8x8 casserole dish or deep dish pie pan and top with potatoes. Top with second pie crust (omit for Whole 30 or GF).
If using pie crust: Bake for 15 minutes at 425° or until crust is golden brown.For Whole 30 of GF: Broil on high for 5 minutes to brown the potatoes (optional)
To freeze: Place in an aluminum pan with paper lid. To reheat: Thaw overnight in the fridge and bake on 375° for 30 minutes OR place directly into cold oven from the freezer and heat to 375°. Bake for an additional 45-60 minutes.
Easy Shepherd's Pie https://www.amodernhomestead.com/easy-shepherds-pie/