Beef Stroganoff with Straw Potatoes

by Nadia Kim

4 servings

Mustard Sour Cream Sauce

• 30 mlunsalted butter
• 30 mlall-purpose flour
• 5 mldry mustard powder
• 235 mlbeef stock
• 59 mlsour cream

Beef

• 30 mlunsalted butter
• 1small yellow onion
• 680 gbeef tenderloin
• kosher salt
• black pepper

Straw Potatoes

• 4russet potatoes
• kosher salt
• 30 mlparsley