In a large oven-safe skillet, heat the olive oil over medium-high heat. Add in the garlic and cook for about a minute before adding in the onion, celery, and carrot. Cook the vegetables for another 2-3 minutes, or until softened.
Add in the ground beef. Cook, breaking the beef up until no pink bit remain. Add in the peas, wine, diced tomatoes, tomato paste, broth, bullion cube, Worcestershire sauce, and thyme.
Brink the mixture to a simmer over medium and cook for 25-35 minutes (stirring every few minutes) until the mixture has thickened. Remove from heat.
Preheat the oven to 350 degrees F.
In a pot over medium heat, melt together the cream, sour cream, and butter.
While the meat is cooking boil the peeled potatoes in slightly salted water for 10-15 minutes until soft, do not overcook. Drain, then mash together with the melted cream, sour cream, and butter.
Dollop the mashed potatoes over the top of the skillet with the filling, and smooth out the top
Use a fork to add marks into the top of the mashed potatoes or leave as is.
Bake in preheated oven for 25-30 minutes or until the potatoes are golden brown and the edges are bubbling. Broil for 1-2 minutes on high to get the very tops of the potatoes crispy!