Heat 2 tablespoons of extra virgin olive oil in a medium sized (4 1/2 quart) Dutch oven. Once hot, add the ground beef with 1/2 teaspoon of salt and a few grinds of fresh pepper.
Cook the beef through, breaking up the large pieces with a spatula, then remove the cooked beef and place in a small mixing bowl. Keep the olive oil and beef drippings in the Dutch oven for the next step.
Change to medium heat and add the finely diced onion, shallot, carrots, and celery to the Dutch oven. Add the fresh thyme leaves and stir. Season with a generous pinch of salt and black pepper.
Cook until the onions start to turn slightly translucent, while stirring occasionally. Use a garlic press to crush the garlic and add to the pot. Cook for another 30 seconds until the garlic becomes fragrant.
Add the flour to the pot and stir thoroughly. Coat all of the vegetables with the flour and continue cooking for 2-3 more minutes.
Next, add the bone broth, tomato paste, Worcestershire sauce, veal demi glacé, and Irish whisky to the Dutch oven. Stir to combine.
Bring to a boil while stirring occasionally. Once at a boil, lower the heat to a simmer and add the green peas (frozen is fine) and cooked ground beef to the pot.
Let simmer uncovered for 20 minutes. The liquid level should evaporate and thicken to be slightly below the meat and vegetables. Adjust the seasoning and stir occasionally.
While the cottage pie filling simmers, it's time to make the potato topping:
Fill a pasta pot with cold water and add a pinch of salt. Add the cubed potatoes to the pasta pot and place over medium high heat. Let the water come to a boil and cook the potatoes until fork tender.
Drain the potatoes, then, using a potato ricer and large bowl, 'rice' the potatoes to make them airy and smooth.
Heat the half & half and butter in a microwave-safe bowl in 30 second increments until the butter has melted, or heat slowly on the stovetop using a small sauce pan. Add this mixture to the potatoes and stir thoroughly. Season to taste with salt and black pepper.
Shred 6 ounces of sharp cheddar cheese and reserve about 1/3 of a cup to the side. Add the remaining shredded cheese to the potatoes and stir well.
After the cottage pie filling has reduced and thickened, remove from the heat and let cool for 5 minutes.
Preheat your oven to 350F at this point.
Using a large spoon, dollop the mashed cheddar potatoes on top of the filling in one thick layer. You can gently swoop the potatoes with the back of a spoon if desired.
Sprinkle the 1/3 cup of cheddar cheese on top of the mashed potatoes and place the whole cottage pie pot into the oven. Bake uncovered for 25-30 minutes, or until bubbly and golden. I like to also give the potatoes a quick broil after baking, just to add a bit more color.
Remove from the oven and let stand for 10-15 minutes before serving. Garnish with fresh Italian parsley if desired.