1 Preheat oven to 400 degrees F.
2 Melt together butter and oil over medium heat.
3 Add shallot and mushrooms, season to taste with salt and pepper, saut� until mushrooms are browned, about 5 to 7 minutes, then add garlic and saut� for an additional 2 minutes.
4 Add the sherry, stir, saut� until sherry evaporates; remove from heat.
5 Heat a nonstick skillet, drizzle with a little olive oil, and sear both sides of beef (leaving the middles rare) and/or the scallops; set aside and keep warm.
6 Mix together the beaten egg and water to make an egg wash.
7 On a lightly floured board, roll each piece of the puff pastry until they're about 10"x6" big; cut a thin strip, about 1/8th inch thick, from the 6-inch ends of the pastries and set aside for decorative purposes.
8 On each piece of pastry, place half of the mushroom mixture, top with half of the pate, and then either 1 piece of seared beef or 2 seared scallops.
9 Brush the perimeter of the pastry with the egg wash.
10 Gather two opposite corners of the dough together, then the other two, and twist the 4 corners to seal.
11 Loosely tie the reserved strips around the top of each Wellington.
12 Transfer Wellingtons to a parchment or silpat lined baking sheet (a non-stick baking pan should be okay, too), brush each Wellington with egg wash and sprinkle with minced basil.
13 Bake at 400 degrees F until they've turned a golden brown to your preference; remove from oven and let sit on baking sheet for 5 minutes.