Beef Tenderloin Sandwich with Horseradish Aioli, Arugula and Caramelized Shallots

This definitely does not fall into the category of quick & easy, but it's so mind-blowingly good that it's worth the effort once in a blue moon. The butter-basted beef would be delicious on its own so if you opt out of doing the sandwich, at least try the beef prepared this way. This is adapted from Food & Wine magazine.

For the aioli:
I use the recipe for The Creamiest Aioli from Bon Appetit but make the following changes: I press the garlic clove instead of grating; I use 1 t of Dijon mustard; 1 T lemon juice and when it's all done, I stir in 1 t horseradish. I can only successfully make aioli in my mini-cuisinart food processor and have never ever ever had any luck whisking slowly or any other method. If you don't want to bother with this step, you can just add a little horseradish to some purchased mayo or use a mixture of Dijon and horseradish.

For the beef:
2 T canola oil
2 lbs beef tenderloin, at room temp.
kosher salt and pepper
4 T unsalted butter
4 garlic cloves, lightly crushed
pinch of thyme
1 cup beef broth
1 cup red wine
Liberally salt and pepper the beef; preheat oven to 375º. In a cast iron skillet, heat the canola oil and sear the beef until well-browned all over. Add the butter, garlic and thyme and baste the meat with the mixture once the butter has melted. Transfer to the oven and roast for 30 minutes, basting every 5 minutes with the butter. Don't take this roasting time as the gospel-- it depends on the thickness of the meat etc. I think I had leave it in an additional 5 minutes.  Remove the meat from the pan and let it rest covered.
Heat the skillet with the beef drippings over high heat and add the beef broth and red wine; boil this until reduced and thickened-- approximately 10 to 15 minutes. Add salt and pepper to taste.

For the sandwich:
ciabatta bread, sliced in half horizontally
sliced cheese of your choice- provolone is nice or a combo of a couple of cheeses
arugula
caramelized shallots
horseradish aioli
butter-basted beef
red-wine pan sauce
Preheat the broiler; on both halves of the bread, spread a thin veneer of the aioli, add a layer of shallots and then arugula. Top with lots of sliced cheese to cover it all; broil until the cheese is bubbly. Lay some beef on one half of the bread and drizzle with the pan sauce. Assemble and then cut into individual servings.