Preheat oven to 350 degrees. In a large, high-sided, oven-safe skillet, add the bacon and cook over medium-high heat until fat is rendered and bacon is crispy. Remove bacon with a slotted spoon to a paper towel-lined plate and set aside.
Add the onion and carrots and sprinkle with kosher salt. Cook until softened, about 5 minutes. Add the garlic and cook for 1 minute more. Add the wine and cook until reduced by half, about 3 minutes, then stir in the flour until all the vegetables are coated.
Add the ground beef and cook until no longer pink, breaking up the meat as it cooks, about 5 minutes. Stir in the tomato paste until coated and cook for 1 minute more. Carefully add the beef broth and worcestershire sauce and stir until combined. Add the peas, thyme, rosemary, and black pepper, as well as the reserved crispy bacon and stir well.
Top with the mashed potatoes in a single, thick, even layer, then place in the oven and bake for 30 minutes, or until golden and bubbly. Let sit 5 minutes before serving and enjoy!