Chop all the herbs and veggies and set aside. Place two skillets over medium heat. In a mixing bowl, mix all the ingredients for the potato pancakes, along with 1/2 teaspoon salt and 1/4 teaspoon ground pepper.
In one skillet, add 2 tablespoons butter, followed by the mushrooms, garlic and thyme. Stir and allow the mushrooms to often a bit, then salt and pepper to taste. Add the sherry. Continue cooking, stirring occasionally, until the sherry is completely adsorbed and the mushrooms start to caramelized.
Meanwhile, place a small pat of butter in the second skillet. Swirl the melted butter around, then add 1/2 cup potato batter. Cook until the bottom is golden and the sides are firm. Then flip and continue cooking, 2-4 minutes per side. Repeat with the remaining batter.
Once the boxties are finished cooking, add 2 tablespoons each of butter and flour to the same skillet. Whisk and bubble for 1-2 minutes, then add the Irish whiskey, stock, and mustard. Continue whisking the gravy until your desired consistency is reached. Salt and pepper to taste.
To serve: Place one boxty on each plate. Evenly distribute the sautéed mushrooms on top of each boxty and fold over. Pour warm gravy over the potato pancakes and serve immediately.
To Freeze: Make potato pancakes per the recipe, and once cooled store in an airtight container, either individually wrapped in plastic wrap, or with parchment paper in between pancakes to keep from sticking together. Keep in the freezer for up to 4 months.