Vegetarian, but love the idea of a puff pastry covered yummy holiday dish? Then this is your entree. It still has the delicious cooked cremini mushrooms, but the only change is instead of using beef (and prosciutto), you use beef. (note: puff pastry is not vegan though.)
Ingredients
- 1 lb., 2 oz. beets (about 3 large ones)
- 2-1/4 tsp. kosher salt, divided, plus more as needed
- Scant 1/2 tsp. black pepper, divided, plus more as needed
- 8 Tbs. (1 stick) unsalted butter, divided
- 2 shallots, minced
- 2 lb. cremini mushrooms, stems discarded and caps finely minced
- 1/4 cup English Mustard
- 5 cloves garlic, minced
- 1 sheet puff pastry, defrosted
- 2 eggs, beaten
Directions:
Heat the oven to 400°F. Wrap the beets in aluminum foil and roast until they’re just barely cooked through, about 50 minutes (you should be able to poke a fork in about 1/2 inch with some resistance). Remove and allow to cool slightly to remove the skills. Make sure they are cool enough to handle.
In a pan, add butter, mushrooms, shallots, and garlic and cook over medium heat. Cook, stirring occasionally, until all the liquid evaporates and the mushroom mixture becomes
a thick, dry-like paste. Remove the mushrooms from the pan and let cool completely. 
Unfold defrosted pastry on a clean, floured surface. Roll out just a bit. Brush the mustard on all sides of the pastry. Spread the cooled mushroom mixture.
Then add the cooled, cooked beets.
Fold the dough over the edges to cover the vegetables. Transfer to a parchment-line baking sheet. Brush the surface with the beaten eggs. score with a decorative design.
(note: if you were making this ahead of time, you would be okay to chill this for 45-2 hours beforehand, but I did not for time reasons.) 
Bake at 400 degrees until the pastry is golden brown brown and puffed. (Since you know the beets are cooked, you want to make sure the pastry is cooked… about 40-50 minutes.)
Allow to rest enough to be able to cut and serve. Serve warm with a great glass of red wine.
Roast 'n Relish 