Fancy French Onion Beef Tenderloin

🥘 Ingredients

• asparagus
  12 oz
• beef stock concentrate (divided)
  2 unit
• beef tenderloin filets
  20 oz
• butter (2 TBSP for 4)
  2 tbsp
• cooking oil (divided)
  4 tsp
• creamy horseradish sauce
  2 oz
• dried thyme (divided; ½ tsp for 4 servings)
  2 tsp
• fingerling potatoes
  24 oz
• garlic powder
  2 tsp
• lemon
  2 unit
• mayonnaise
  4 tbsp
• pepper
• rosemary (chopped)
  ¼ ounce
• salt
• sour cream
  3 tbsp
• sugar (divided)
  2 tsp
• yellow onion (thinly sliced)
  2 unit

🍳 Cookware

• baking sheet
• medium pan
• large pan
• medium bowl
• medium bowl
• baking sheet
• cutting board

1. 

   1

   Adjust rack to middle position (top and middle positions for 4 servings) and preheat oven to 450 degrees. Wash and dry produce. Halve fingerling potatoes lengthwise. Strip rosemary leaves from stems; finely chop rosemary leaves until you have ¼ tsp (½ tsp for 4). (We sent more; save the rest for another use!) Halve, peel, and thinly slice yellow onion . Zest and quarter lemon . Trim and discard woody bottom ends from asparagus .

   fingerling potatoes: 24 oz, rosemary: ¼ ounce (chopped), yellow onion: 2 unit (thinly sliced), lemon: 2 unit, asparagus: 12 oz
2. 

   2

   Toss potatoes on one side of a baking sheet with a drizzle of cooking oil , chopped rosemary, salt , and pepper . Roast on middle rack for ⏱️ 14 minutes (you'll add the asparagus then). (For 4 servings, spread potatoes out across entire sheet.)

   cooking oil: 4 tsp (divided), salt, pepper
3. 

   3

   Meanwhile, heat a drizzle of oil in a medium pan (use a large pan for 4 servings) over medium-high heat. Add onion and ¼ tsp dried thyme ; cook, stirring occasionally, until browned and softened, ⏱️ 5-8 minutes . Stir in beef stock concentrate , ¼ cup water, sugar , and 1 tsp lemon juice (for 4, use ½ cup water, 2 tsp sugar, and 2 tsp lemon juice). Cook until thickened and saucy, ⏱️ 2-3 minutes more. Remove from heat; stir in 1 TBSP butter until melted. Taste and season with salt and pepper if desired. Transfer to a medium bowl ; it should be microwave-safe; tightly cover with plastic wrap. Rinse and wipe out pan.

   dried thyme: 2 tsp (divided; ½ tsp for 4 servings), beef stock concentrate: 2 unit (divided), sugar: 2 tsp (divided), butter: 2 tbsp (2 TBSP for 4)
4. 

   4

   While onion cooks, in a second medium bowl , combine sour cream , creamy horseradish sauce , mayonnaise , and a squeeze of lemon juice. Season with salt and pepper to taste. Pat beef tenderloin filets dry with paper towels and season generously all over with garlic powder , ½ tsp dried thyme (1 tsp for 4 servings), salt, and pepper. (Be sure to measure the thyme - we sent more!)

   sour cream: 3 tbsp, creamy horseradish sauce: 2 oz, mayonnaise: 4 tbsp, beef tenderloin filets: 20 oz, garlic powder: 2 tsp
5. 

   5

   Once potatoes have roasted ⏱️ 14 minutes , remove sheet from oven. Carefully toss asparagus on opposite side with a drizzle of oil, salt, and pepper. Return to middle rack and roast until veggies are lightly browned and tender, ⏱️ 10-12 minutes more. (For 4 servings, leave potatoes roasting; add asparagus to a second baking sheet and roast on top rack.)
6. 

   6

   Heat a drizzle of oil in pan used for onion over medium-high heat. Add beef and cook to desired doneness, ⏱️ 4-7 minutes per side. Transfer to a cutting board and let rest for a few minutes.
7. 

   7

   If necessary, reheat saucy onion in the microwave, ⏱️ 15-20 seconds . Toss asparagus with as much lemon zest as you like. Slice beef against the grain. Divide beef, asparagus, and potatoes between plates. Top potatoes with saucy onion and drizzle beef with as much horseradish cream as you like. Serve with remaining lemon wedges on the side. Beef is fully cooked when internal temperature reaches 145 degrees.