We all know the FFMM, grass-fed beef burger. We all love the FFMM, grass-fed beef burger. And yes, often all you need to get the best out of it is a slice of cheese and some good pickles. But sometimes you really want to show off. Sometimes you want to let your hair down and howl at the burger moon. When that mood strikes, listen to your bad self. Get crazy. Make the sauce below to next-level things. 

What you'll need: 

1 x medium white onion, finely diced
2 x cloves garlic, minced
2 x sprigs fresh thyme
1 x Tbs Olive Oil
1/2 x Cup Red Wine
1/2 x Cup Beef Stock
1 x tsp Dijon Mustard
800g beef marrow bones, sliced into discs
Sea salt, to taste
Black pepper, to taste
Chives, finely chopped, to garnish 

What you'll do:

1. Preheat oven to 220 Degrees Celsius. 
2. Line a baking tray with tin foil and Rub enough olive oil onto marrow to coat both sides of exposed meat. Season well with sea salt and black pepper. 
3. Roast marrow for 20 - 25 minutes, or until softened but still holding its shape inside the bone. Remove and allow to cool. 
4. Meanwhile, heat oil in a pan over medium heat. Add onion and soften for a few minutes, before adding garlic and doing the same. You don't want colour on these. 
5. Add the red wine and thyme and increase heat slightly. Cook for 5 minutes, before adding beef stock. Cool for a further 5 -10 minutes or until reduced by about half. 
6. Meanwhile, remove marrow from bones with a teaspoon. It should come loose easily. 
7. Add marrow and mustard to the sauce and decrease heat, allowing the sauce to incorporate. 
8. When you're happy with the consistency of your sauce, remove and keep warm. Garnish with chives. 
9. Plate up your burger according to how you like it and add a big spoon of the sauce, just before serving.