Begin by peeling and cutting the Russet potatoes into even-sized chunks for consistent cooking. Place the potato pieces in a large pot of salted water and bring to a boil over medium-high heat. Cook for about 15-20 minutes until fork-tender; drain well and allow them to steam for a few moments to remove excess moisture.

In a mixing bowl, add the drained potatoes. Mash them vigorously with butter and milk until the mixture is smooth and creamy, but thick enough to hold its shape when molded. Stir in fresh thyme, salt, and pepper to taste.

Preheat your oven to 400°F (200°C). Grease a standard muffin tin generously with butter or oil.

Carefully press the creamy mashed potatoes into the greased muffin tin, creating a hollow center in each cup for the sausages. Ensure the potato mixture is packed tightly. Place your pre-cooked Irish sausages into the hollow sections.

Place the muffin tin in the preheated oven and bake for 25-30 minutes or until the tops of the cups are golden brown and crispy.

Once baked, remove the muffin tin from the oven and let the cups cool for a few minutes. Run a butter knife around the edges to loosen them before gently lifting each cup out. Serve warm, garnished with fresh herbs.