LEFTOVER STEAK AND MUSHROOM PUFF PASTRY: A VERY GOOD SECOND ACT

A very good second act: a golden steak and mushroom turnover with green salad

A grey steak, a vocal smoke alarm and a sheet of puff pastry turn a disappointing dinner into golden steak and mushroom turnovers.

A great steak—and a small problem

One of our most popular posts is “Forget Everything You Know About Cooking a Great Steak.” Readers tell me they don’t use any other method. If you haven’t tried it, do take a look. We use it to great effect at our house in Bridgehampton, where the range hood takes care of the smoke.

Our New York stove, unfortunately, might as well be aimed at the smoke alarm. So when I read that shell steaks could be cooked in the oven, I thought I had found a solution. Alas, most methods began with searing the steak on the stovetop—the very thing I wanted to avoid.

I tried an oven-only approach, cooking the steak to an internal temperature of 135°F. It tasted quite good but had all the appetite appeal of a grey piece of meat. Then opening the oven set off the fire alarm. An unattractive steak and the usual commotion: quite an achievement.

Puff pastry to the rescue

Fortunately, I had leftover steak and puff pastry at the ready. Chopped mushrooms, onion, garlic, thyme and a little Dijon supplied the filling for four golden turnovers. With a green salad alongside, the beef had a much more promising second act.

You don’t need a disappointing steak to make these. Any leftover cooked steak will do. Cook the moisture out of the mushrooms, cool the filling completely and keep the pastry cold. The beef needs no further frying; it will heat through as the pastry bakes.

I still recommend our original steak method. But for leftovers, a little pastry works wonders. If only it could do something about the smoke alarm.

Leftover Steak and Mushroom Puff-Pastry Turnovers

October 8, 2026

Servings: 4

Prep: 15 min

Difficulty: Aside from the chopping, this is a very easy dish to pull off

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Turn leftover steak into golden puff-pastry turnovers with mushrooms and Dijon. An easy way to give good beef a delicious second act, served with a green salad.

By: Monte Mathews

Ingredients

• 6–8 ounces cooked steak, cut into small pieces
• 8 ounces cremini mushrooms, chopped
• ½ medium onion, chopped
• 2 garlic cloves, minced
• 1 tablespoon olive oil
• ½ teaspoon dried thyme
• Freshly ground black pepper
• 1 teaspoon Dijon mustard
• Salt, only if needed
• 1 sheet puff pastry, thawed but kept cold
• 1 egg, beaten, for sealing and brushing the pastry

Directions

• Step 1 Prepare the filling. Cook the onion and mushrooms in the olive oil until the mushrooms’ liquid has evaporated and they begin to brown. Add the garlic and thyme for the final minute. Remove from the heat and stir in the cold cooked steak and Dijon mustard. Season with black pepper and add salt only if needed. Let the filling cool completely.
• Step 2 Prepare the pastry. Heat the oven to 400°F and line a baking sheet with parchment. Keep the puff pastry cold and cut the sheet into four squares.
• Step 3 Fill and seal. Divide the cooled filling among the squares, using only as much as will fit comfortably and leaving the edges clear. Brush the edges with beaten egg, fold each square diagonally into a triangle and crimp the edges to seal. Place on the prepared baking sheet. Brush the tops with egg and cut a small vent in each turnover.
• Step 4 Bake. Bake for about 20–25 minutes, until risen, deeply golden and cooked on the underside. Serve with a green salad.