Grilled Marinated Beef Fillet With A Tangy Sauce

• 4 steak fillets
• 1/4 cup balsamic vinegar
• 4 -5 tablespoons olive oil
• 1 1/2 teaspoons Dijon mustard
• 1 1/2 teaspoons grainy mustard
• 1 1/2 teaspoons beef bouillon granules (I use quite a dense stock, so adjust for taste, with what you use.)
• 1/2 cup water
• 1 tablespoon sugar (generous)
• 1 teaspoon cornflour
• 100 ml sour cream
• pepper

1. Combine vinegar, oil and mustard's in storage container add steaks and marinate several hours or overnight.
2. Drain beef and reserve marinade. In a medium saucepan add stock, sugar and water to reserved marinade. Heat over medium heat until sugar dissolves. Mix a little water with cornflour and add to sauce, stir until mixture thickens. Keep warm over low heat stirring occasionally. If sauce seems to be getting too thick add a little more water, not to much though, as remember you still have to add the sour cream which will thin it out again.
3. Heat a small amount of olive oil in a pan over med high heat (or grill or BBQ) add the steaks and sear 1-2 minutes each side. Cook for a further 4-5 Min's a side for medium rare. Cooking time will vary depending on the thickness of the meat. Remove steaks and allow to rest.
4. While the steak rests, turn up the heat on the sauce and whisk in sour cream (this will also blend in any mustard that is still a little lumpy.), add pepper to taste.
5. To serve: Place a few spoonfuls of desired mash in the centre of a plate, place steak on top and top with a mound of spinach, drizzle with sauce.

balsamic vinegar, olive oil, mustard, grainy mustard, beef bouillon granules, water, sugar, cornflour, sour cream, pepper

Taken from www.food.com/recipe/grilled-marinated-beef-fillet-with-a-tangy-sauce-269522 (may not work)