Thanksgiving Recap And Marc’s Beef Demi Mushroom Tart

Thanksgiving this year was small and relaxed. Six of us at the table, a little sore from a local Turkey Trot 5k and very ready to eat. The turkey turned out great. The brine, on the other hand, tried to escape the bag and ended up all over the kitchen. We cleaned up, laughed about it, and kept cooking.

I worked Offcuts Kitchen into a few parts of the meal. For the gravy, I made a simple roux, whisked in chicken stock, then added a spoonful of our chicken demi. It brought real roast flavor and body without needing a separate stock pot on the back burner all day.

The surprise hit of the night was a mushroom tart my brother Marc put together with puff pastry, a pan of sautéed mushrooms, and our beef demi. It landed on the counter and disappeared fast. Everyone went back for seconds and we already agreed it will be back for Christmas. I posted a simplified version of the recipe, as I realized that I am terrible at describing platting. 

Below is Marc’s recipe, written from his memory of making it on Thanksgiving, with a few clarifying details added.

Marc’s Beef Demi Mushroom Tart

Ingredients

• 1 sheet frozen puff pastry, thawed according to package directions
• 12 to 16 ounces mushrooms, chopped (cremini, button, or a mix)
• 2 tablespoons butter
• 2 to 3 tablespoons Offcuts Kitchen beef demi
• 1 teaspoon fresh or dried thyme
• Salt and freshly ground black pepper, to taste
• 1 egg, beaten with a splash of water, for egg wash

Instructions

1. Take the puff pastry out of the freezer so it can defrost according to the package instructions.
2. Heat the oven to 400°F, or to the temperature recommended on your puff pastry box. Line a baking sheet with parchment paper.
3. In a large skillet, melt the butter over medium heat. Add the chopped mushrooms, thyme, salt, and pepper. Cook, stirring occasionally, until the mushrooms have released their liquid and most of the water has cooked off. You want them tender and a little glossy, not watery.
4. Spoon the beef demi over the mushrooms, about 2 to 3 tablespoons, and stir to coat. Taste and adjust the seasoning with a bit more salt or pepper if needed. Take the pan off the heat and let the mushrooms cool on the stovetop so they are warm, not piping hot.
5. On a lightly floured surface, roll out the puff pastry until it is an even thickness and slightly larger than when it came out of the package. You want a rectangle that will fit comfortably on your baking sheet.
6. Spoon the mushroom mixture into an even layer over one half of the pastry, leaving a small border around the edges. The other half will fold over the top like a lid.
7. Fold the empty half of the pastry over the mushrooms to make a pocket. Press along the edges with your fingers, then crimp lightly with a fork to seal so the filling stays put.
8. Carefully move the tart onto the parchment lined baking sheet. A wide spatula or the back of another baking sheet works well here.
9. Use a sharp knife to cut a few small slits in the top of the pastry. These vents let steam escape and help prevent the tart from getting soggy as it bakes.
10. Brush the top of the pastry with the egg wash, making sure to coat it evenly so it browns nicely.
11. Bake at 400°F until the pastry is puffed, deep golden brown, and the filling is hot. Start checking around 20 minutes and give it a few more minutes if needed.
12. Let the tart cool for a few minutes on the baking sheet, then slice and serve while it is still warm and flaky.

You can use whatever mushrooms you have on hand here, from basic buttons to a mix of cremini and shiitakes. The key is giving them time in the pan and finishing them with a spoonful of demi. If you want to make this exactly the way we did, grab a jar of our 100% Grass-fed Beef Demi-Glace from the shop and keep it in the fridge for the next round of “what did you put in this” moments.