Heat olive oil over medium heat in a large saute pan.
Add in onions and carrots, cooking until softened, about 7-10 minutes.
Add in garlic and ground beef, breaking up with your spoon; cook 4-5 minutes until no longer pink.
Add in flour, stir and cook 1 minute.
Mix in Worcester, all spice, salt and pepper.
Add in corn and peas, mix to combine and set aside while you make the mashed potatoes.
Fill a medium saucepan ¾ with water. Bring to boil.
Add in potatoes and cook for about 10 minutes until fork tender.
Drain and set aside.
In the same pan, return back to medium heat and add butter. Continue cooking until fully melted. Keep cooking, as you stir, until you see it start to foam and notice brown specks. It will have a nutty aroma. It should take up to 5 minutes for this process
Add potatoes to the butter and rosemary.
With hand mixer or potato masher, mash potatoes until no longer lumpy.
Gradually add in the milk and grated cheese until desired consistency.
Season with salt and pepper to taste.
Place meat mixture in 9-10” pie plate or a 9x9 square baking dish. Top with pumpkin mashed potatoes.
Bake at 350 until mixture is bubbly and top is slightly browned.