---
title: Sirloin Steak "Diane" with Dijon-Mushroom Sauce
source:
  name: HelloFresh
  url: https://www.hellofresh.com/recipes/sirloin-steak-diane-with-dijon-mushroom-sauce-698f602e753621b2c23a1759
servings: 2
prep time: 15 minutes
cook time: 35 minutes
time required: 50 minutes
difficulty: Medium
allergens:
  - Milk
tags:
  - Protein Smart
  - Beef
  - Steak
  - Date Night
rating: 0.0
rating_count: 0
source_chef: Recipe Development Team
review_highlights:
  - theme: Flavor
    text: Deep, rich, and gloriously meaty steak flavor
  - theme: Comfort
    text: Ultra-creamy mashed potatoes and tender roasted carrots
image: "https://images.recipes.furrysalamander.com/sirloin-steak-diane-with-dijon-mushroom-sauce.avif"
---
Wash and dry all produce. Peel and dice potatoes. Quarter onion. Trim and halve carrots lengthwise. Wipe mushrooms clean. Mince garlic.

Adjust rack to top position and preheat oven to 425°F. Toss @carrot{8%oz} on a #baking sheet{} with a large drizzle of @cooking oil{2%tbsp}, @salt{1%tsp}, and @black pepper{1%tsp}. Roast on top rack until browned and tender ~{25%minutes}.

While potatoes cook, heat a large drizzle of oil in a #large pan{} over medium-high heat. Add @onion{1%unit} and cook, stirring occasionally, until browned and softened ~{8%minutes}.

Pat @sirloin steak{12%oz} dry with paper towels; season with salt and pepper.

Add @butter{2%tbsp} and @button mushrooms{6%oz} to same pan over medium-high heat. Cook, stirring, until browned and softened ~{3%minutes}. Stir in @garlic{2%cloves} ~{30%seconds}. Add @beef demi-glace{2%tbsp} and @dijon mustard{1%tbsp}, scraping up browned bits. Remove from heat and stir in @sour cream{2%tbsp} and @sugar{1%tsp}.

Slice steak against the grain. Mash potatoes until creamy. Divide between plates with carrots. Spoon mushroom sauce over steak.