¾ cup beef stock (can use Chicken or Vegetable stock)
½ cup dark beer (can substitute with more water if desired)
½ cup water
2 tablespoons fresh sage, chopped
1 sheet frozen puff pastry, thawed
Toss beef with 2 tablespoons of flour, ½ teaspoon salt and ½ teaspoon pepper until all pieces are well coated. Discard any additional flour. Heat a large heavy pot over medium-high heat. Add oil and heat until it begins to shimmer. Add beef and sear until all sides are browned.
Remove beef from pan and set aside. Turn heat down and add onions, carrots and celery. Saute until onions are translucent and vegetables are softened. Add mushrooms until tender, then garlic, sautéing until fragrant.
Slowly deglaze pan with beer.
Return the beef to the pot and add the Portobello Sauce, stock and water, stir. Reduce heat to low, cover and simmer for 1 hour, until meat falls apart with the pressure of a fork. Season with salt and pepper to taste.
Preheat oven to 400°F
Combine 2 Tablespoons flour with 2 Tablespoons cold water. Bring pot pie mixture back to a low boil and slowly stir in flour/water mixture and allow to thicken. Once the sauce has thickened, add sage and mix well. Remove from heat and pour into casserole dish.
Top with thawed puff pastry (you can cut this to the size of the dish, or you can drape the edges over the sides) brushed with olive oil and sprinkled with sea salt. Bake for 35 minutes, or until puff pastry has browned.