Place everything except the mushrooms and butter in a food processor and blend until smooth.
Melt 1 tbsp of butter in a medium sized frying pan over low heat then pour in the tofu mixture; use a spatula to spread the mix till it covers the bottom. Cook for 11 minutes; flip and cook another 5 minutes.
Heat the remaining butter in another small pan over low heat and saute the sliced mushrooms for about 5 minutes.
Plate the omelette and fill with the mushrooms, then fold over to enclose the filling. Enjoy!