Shepherd's Pie II

This is one of my all time favorite comfort foods. I loved it growing up, and now there are so many recipes out there for twists and turns to add even more deliciousness. I call this shepherd's pie "II" because it is a recipe that I found that is different from the one my mom makes, but a new favorite with the husband and kids.... I will post "Shepherd's Pie I" soon for comparison. (backwards, I know - but so goes my life!) 1 1/2 lbs. potatoes, peeled and cut into cubes.
1/2 c. milk
1 T butter (or more to taste)
salt and pepper
1 lb. lean ground beef
1 medium zucchini, chopped
1 small onion, chopped
1 clove garlic, chopped
1/2 c. smoky bbq sauce ( I like KC Masterpiece )
1 t. yellow mustard
1 t. brown sugar
1 1/2 c. corn, fresh or frozen, (thawed, if frozen).
chopped cilantro or scallions for garnish

Put potatoes in a pot of water and bring to a boil. Cook for about 15 minutes, or until done. Drain and mash with milk and butter until creamy. salt and pepper to taste. Set aside. Preheat oven to 400 degrees and grease a 9x13 casserole pan. In a large saucepan, cook meat with zucchini, onions, and garlic, until meat is just cooked. Drain if necessary. Stir in bbq sauce, mustard, and brown sugar. Transfer to prepared casserole dish. Scatter corn evenly on top. Spread potatoes carefully over top and sprinkle with cheese. Bake at 400 degrees, until filling is bubbly and cheese is just melted, about 20 minutes. (you don't want the cheese to get hard and crusty!).
Feel free to share your variation to the above, I would love to try it!