Heat olive oil in a pan over medium heat. Add chopped onions and carrots, saut? until softened.

Stir in the shredded corned beef, Worcestershire sauce, and beef broth. Cook for about 10 minutes, allowing flavors to meld.

Add peas and stir to combine. Remove from heat.

Boil the cubed potatoes in a pot of salted water until tender, about 15-20 minutes.

Drain the potatoes and return them to the pot. Add warmed milk, butter, salt, and pepper. Mash until smooth.

Preheat the oven to 400?F (200?C).

Spread the corned beef filling evenly in a baking dish. Top with the mashed potatoes, smoothing out the surface.

Bake in the preheated oven for 25-30 minutes, or until the top is golden brown.

Let cool for a few minutes before serving.