Best Ever Fillet Marinade

Ingredients
1 teaspoon minced ginger
1 tablespoon minced garlic (try use fresh cloves if you can)
½ cup soy sauce
½ cup water
¼ cup Cornstarch (eg. Maizena)
¾ cup dark brown sugar (you can also use normal brown sugar if you don’t have the dark version)
500g fillet (if you have more or less, that’s fine)
10-12 spring onions, chopped (white part only)
5ml oil and 5ml butter for frying

Directions
Mix the cornstarch and water together to form a paste.
Add the rest of the ingredients (except the oil and butter) to the cornstarch paste and stir well.
Pour into a pan over medium-high heat. Let the sauce come to the boil and then remove from heat and pour the marinade over the fillet in a suitable marinating dish.
All to marinate in the fridge for 4-6 hours (cover with cling wrap or similar)
To cook (this is my secret for cooking fillet): Turn oven on to 220C and in the meantime, place butter and oil in a frying pan and turn heat on high.
Once the pan is hot, lift the fillet out the marinade and seal the fillet by braising it on each side: front, back and sides. This is quite a quick process, it shouldn’t take more than 2-3 minutes – you just want to brown the fillet to add flavour.
Once all the sides are done, place it in an oven roasting/stainless steel dish and pour the marinade in as well as we’ll be using this for the sauce later.
You may need to add a little water to the marinade to thin it out ie. use ⅓ cup water and stir. I did this and it worked out great.
Place in the oven and cook for 10-12 minutes depending on how well done you like your fillet. I always cook my fillet like this because it stays juicy and succulent but still has the yummy taste of the braised meat. Noms! Serve with a plain and simple mashed potato and your choice of veggies

Source : allrecipes.com