Melt butter in a pot on medium low heat, cook onion until softened, about 2 minutes. Add rosemary and cook for 30 seconds.
Add Anchor Extra Yield Cooking Cream and Anchor Cream Cheese, cook on low heat, stir well until cream cheese are all incorporated.
Lastly, season with salt and pepper to taste, add truffle oil and mix well. Keep warm aside, covered.
Toast bun till golden brown.
WIth a non-stick pan, sprinkle shredded parmesan to at least 2 inches bigger than the diameter of the burger bun, place the crown on the bun on parmesan cheese (toasted side up). Cook on low heat until parmesan starts to turn golden brown.
Remove from pan, place bun on a tall heat-proof item, adjusting the parmesan to hang down nicely. Leave it for 2-3 minutes until the cheese hardens.
Using a soft brush, dust the crown with edible gold dust gently. This step is optional.
Mix all batter ingredients until homogenous.
Season sliced king mushroom, dredge it with flour, dip in batter, and deep fry in pre-heated fryer to 180C for 2-3 minutes until golden brown, remove from oil and place on kitchen towel.
Allow minced beef to be in ambient temperature for 30mins.
Season with salt and pepper, grill each side for 2-3 minutes, until desired doneness. Allow to rest for 1-2 minutes.
Spread some mayonnaise on the burger heel, top with arugula, cooked patty, spread with truffle cream sauce, lay 2-3 pieces of king mushroom crisp, more arugula then sliced tomato, finish off with the burger crown and serve with desired dishes. Enjoy!