Beef Wellington Sandwich

Beef Wellington is a classic holiday centerpiece, and for good reason. Juicy beef tenderloin, earthy mushrooms, sharp mustard, and salty prosciutto, all wrapped in flaky, buttery puff pastry. Even without a ribbon, beef Wellington is the ultimate gift. But its preparation and its price can be prohibitive. The tenderloin needs to be only partially pre-cooked so it neither comes out raw nor overcooks once baked in the tastry. The pastry itself must be cold. The mushroom duxelles will ruin everything if they aren't sufficiently dry. And the risk of making a mistake comes at the cost of a famously expensive piece of meat. Surely, I thought, there must be an easier and faster way to capture all the flavors of this classic dish without the stress and the price tag. As always, when I'm looking for answers in life, I look to sandwiches. 

My love for sandwiches is lifelong. They're endlessly riffable, portable, and appropriate at any time of day, and are an excellent vehicle for just about anything. I started thinking about how to translate beef Wellington into a sandwich. Sliced roast beef—homemade or from the deli—gets the job done perfectly. I used very thinly sliced London broil, but you can slice it to your preference. Prosciutto adds salty, fatty richness to the sandwich, and I wanted to layer it on top of the beef so the warm mushrooms could slightly soften the slices and bring out their flavor. Wellington is traditionally slathered in sharp Dijon mustard, so I made a sauce with equal parts Dijon and mayonnaise, plus a bit of horseradish for heat. Peppery arugula complements the kick of horseradish and provides a pop of much-needed color.

To replicate the flaky puff pastry exterior of traditional beef Wellington, I used a simple croissant. I cut them lengthwise, then split them open on a baking sheet to dry them out slightly for a satisfyingly crisp bite, even when sauced. 

The last essential element of this sandwich is the mushrooms. In a beef Wellington, the mushrooms are prepared as a duxelles: finely chopped and cooked in a skillet with butter until softened and thickened to a paste-like consistency. Here, I skip the duxelles both because I prefer the flavor and heft of cooked sliced mushrooms in a sandwich, and also because no one wants to prepare a duxelles just for a sandwich. 

This recipe is easily scalable for eight or 40, depending on who you're feeding. And a great tip from my husband and in-house taster: Make these on mini croissants for an adorable party snack.