Begin by peeling and dicing your Russet potatoes into even chunks. Place them in a pot of cold salted water, bringing it to a boil. Cook for about 15 minutes or until tender when pierced with a fork. Drain and return them to the pot, adding butter, sour cream, milk, and salt. Mash until creamy and fluffy, keeping them warm for the topping of your Easy Classic Shepherd's Pie.

In a large skillet over medium-high heat, warm a tablespoon of olive oil. Add the ground beef, season with salt and pepper, and cook for 4-5 minutes, stirring frequently until browned. Next, stir in the chopped onions, carrots, and celery, sautéing for about 3-4 minutes until the vegetables soften and become fragrant. Then, mix in minced garlic, cooking for an additional minute until aromatic.

Stir in a couple of tablespoons of tomato paste, letting it cook briefly to deepen the flavor. Pour in the red wine, allowing it to boil for about 2 minutes to evaporate the alcohol. Next, add Worcestershire sauce and chicken broth, allowing the mixture to simmer on low heat for about 10 minutes.

Once the filling has simmered, stir in the frozen green peas, mixing them well into the beef and vegetable mixture. Taste and adjust the seasoning as needed, adding salt and pepper to enhance flavors.

Preheat your oven to 400°F (200°C). In a baking dish or large skillet, spoon the savory beef mixture evenly. Carefully spread the creamy mashed potatoes over the top, using a spatula to create ridges and valleys for better browning. Place the dish in the oven and bake for 25-30 minutes or until the potatoes turn golden-brown.

After baking, allow the Easy Classic Shepherd's Pie to cool for a few minutes—this helps the filling set slightly. Garnish with chopped fresh parsley or chives for a pop of color and freshness.