Whisk together 2 tsp KEEN’S Mustard Powder, flour, eggs, chives and milk. Allow batter to rest for 10 minutes.
Sprinkle the beef fillet to taste with McCormick Sea Salt and Black Pepper, then rub with remaining 2 tsp of KEEN’S Mustard Powder and 1 tbsp of olive oil.
Place beef in a medium (180°C fan forced) oven for 50 - 60 minutes or until cooked to your liking remove and let rest while cooking puddings. Increase oven temperature to 230°C fan forced.
Divide remaining oil between 6 standard muffin pan holes and place in hot oven for 10 minutes or until oil is smoking. Carefully fill muffin cups ½ way up with batter and return to oven for a further 15 - 20 minutes or until puffed and golden brown.
Serve sliced beef with Yorkshire puddings filled with gravy and steamed brussels sprouts.
Add 2 tsp of KEEN’S Mustard Powder to your gravy mix for an extra flavour hit.