Heat 2 cups of water in the microwave until steaming. Place the dried porcini mushrooms in a bowl and add the hot water. Let sit for 15 to 20 minutes.

Strain the porcini mushrooms and liquid through a sieve into another medium bowl. Roughly chop the mushrooms and save the strained liquid.

Preheat oven to 325°F.

Season the brisket with salt and pepper.

Heat 1 tablespoon oil in a Dutch oven over medium-high heat and sear the meat until browned all over. Set aside.

Discard excess liquid (fat) from the pot.

In the same pot, add the onions and carrots. Sauté until starting to soften, about 8 minutes.

Add the brown sugar and flour, stirring to coat and make a roux, about 4 minutes.

Add the brisket and any collected juices back into the pot. Mix with a wooden spoon.

Warm the beef stock and crumble the bouillon cubes into it, whisking until dissolved.

Add the Guinness, stock, balsamic vinegar, porcini mushrooms, and the porcini soaking liquid.

Tie together the thyme, parsley, and bay leaf, and nestle into the pot.

Add 1 teaspoon salt and ½ teaspoon black pepper. Cover and place in the preheated oven for 3 hours.

While the stew is cooking, cook the bacon in a skillet over medium heat until crisp. Drain on a paper-towel-lined plate and roughly chop.

In the same skillet, add the mushrooms and cook until they have released their liquid and start to turn golden. Set aside.

Once the stew is finished, stir in the bacon and mushroom mixture.

Increase oven temperature to 425°F. Grease ramekins or pie dish with butter or cooking spray.

Roll out the first pie dough to about ¼" to ⅛" thickness. Cut circles for ramekins or a larger circle for the pie dish.

Line the ramekins or pie dish with the dough, trimming excess to just reach the top.

Par bake the dough using weights or parchment paper with dried beans for about 12 minutes. Remove from oven and weights.

Lower oven temperature back to 325°F.

Add the beef filling using a slotted spoon, filling until slightly higher than the rim of the dish.

Roll out the remaining dough to the same thickness and cut a circle to cover the dish.

Brush the edges of the par-baked pastry with the egg wash and cover with the dough top. Crimp edges to seal.

Make two large slits in the top dough and add decorations if desired. Brush the top generously with the egg wash and sprinkle with coarse sea salt.

Place on a baking sheet and bake for 40 to 50 minutes until golden.

Remove from oven and place on a baking rack for 10 to 20 minutes before serving.