Roast Fillet Of Beef With Onion Marmalade

• 1 None whole fillet of beef (about 4 1/2 lbs), fat trimmed, neatly tied
• 2 tbsp unsalted butter, at room temperature
• 1 tbsp kosher salt
• 1 tbsp freshly ground black pepper
• None None FOR THE ONION MARMALADE
• 1 lb red onions, thinly sliced
• 2 tbsp extra-virgin olive oil
• 3/4 cup red wine
• 2 tbsp balsamic vinegar
• 1/4 cup sugar

1. Preheat the oven to 475u0b0F. Place beef in a shallow roasting pan. Using your hands, rub butter all over fillet. Sprinkle evenly with salt and pepper. Roast for 30-35 mins for rare or 40-45 mins for medium rare.
2. Remove from oven. Tent with foil and let stand for 20 mins. Remove string and slice thickly.
3. Meanwhile, for the onion marmalade, combine onions and oil in a large skillet. Cook on medium heat about 8 mins until onions are soft, stirring frequently. Season with salt and pepper. Stir in wine, balsamic vinegar and sugar. Bring to a simmer. Reduce heat to low; simmer gently for 40 mins, or until liquid has reduced to a syrup, stirring occasionally. Allow to cool in pan, then transfer to an airtight container. Refrigerate and serve chilled or at room temperature.

fillet of beef, unsalted butter, kosher salt, ground black pepper, onion marmalade, red onions, extravirgin olive oil, red wine, balsamic vinegar, sugar

Taken from recipes-plus.com/api/v2.0/recipes/34673 (may not work)