Chef John's Classic Beef Stroganoff

Ingredients

• 2 pounds sirloin tip roast, cut into 1/2-inch thick strips
• salt and pepper to taste
• 1 tablespoon vegetable oil
• 8 ounces sliced mushrooms
• ½ medium onion, sliced or diced
• 1 tablespoon butter
• 2 cloves garlic, minced
• 1 ½ tablespoons all-purpose flour
• ½ cup white wine
• 2 cups beef broth, divided
• ¾ cup creme fraiche
• 1 tablespoon fresh chopped chives