It's hard to sprint across the baseline to hit a forehand winner when you've got a stomach full of steak.

So it's a good thing you didn't qualify for the U.S. Open.

Now you're free to do what you do best: watch other people play tennis as you sip Honey Deuce cocktails and sample every morsel of food served at the Billie Jean King National Tennis Center in New York — or inside your fridge, if you're watching at home.

Either way, you're going to want Pat LaFrieda's famous filet mignon steak sandwich.

The origin story goes that it was originally Pat's father's favorite sandwich, but he made it with skirt steak, which is the LaFrieda's favorite beef cut. Apparently skirt steak is too chewy for some customers, so they switched to tender filet mignon, and the crowd went wild.

The meat maestro sells an average of 10,000 sandwiches during the tournament each year, so if you're attending, you can do your best to increase that tally. If you're not, no worries — you can make it at home with this recipe.

Pat LaFrieda's Original Filet Mignon Steak Sandwich

Makes 4 sandwiches

Ingredients:

• 4 tablespoons canola or another neutral-flavored oil, plus more as needed
• 2 large sweet yellow onions or Spanish onions, thinly sliced (about 3 cups)
• 6 ounces thinly sliced Monterey Jack cheese
• 1 cup beef stock or demi-glace (store-bought)
• 1 1/2 teaspoons balsamic glaze
• 12 (half-inch thick) medallions tenderloin (about 1 1/2 pounds total)
• 1 tablespoon kosher salt
• 1/2 teaspoon turbinado sugar or light brown sugar
• 4 demi-baguettes, or 6-inch segments of a long baguette

Instructions:

1. In a large skillet, heat 2 tablespoons of the oil over medium heat until it slides easily in the pan, 2 to 3 minutes. Add the onions and cook, stirring occasionally so they don’t stick to the pan, until they are soft and caramelized, about 20 minutes. Spread the onions out over the surface of the pan. Remove from the heat and lay the cheese on top of the onions, letting it melt.
2. To make a jus, in a small saucepan, bring the stock to a simmer over medium heat. Remove from the heat and stir in the balsamic glaze. Cover the pan to keep the jus warm.
3. Season the meat on both sides with the salt and sugar.
4. In another large skillet, heat the remaining 2 tablespoons of oil over high heat. Add half the tenderloin medallions, or as many as will fit in a single layer, and sear them until they are caramelized, 1 to 1 1⁄2 minutes per side. Cook the remaining medallions in the same way, adding more oil and letting it get hot before adding the meat to the pan.
5. Meanwhile, without opening them, toast the baguettes so the outsides, top and bottom, are hot and crispy. Halve the baguettes horizontally, leaving them hinged on one side.
6. To assemble the sandwiches, lay 3 medallions on the bottom of each baguette. Top with the onions and cheese, dividing them evenly among the sandwiches. Drizzle 1⁄4 cup of the jus on the inside top half of each baguette. Close up the sandwiches and you’re good to go.