Method:
Cook the mushrooms down
Heat a wide bottomed non-stick pan on high heat and once hot add 1 tbsp of oil.
Add the mushrooms, along with a good pinch of salt and fry them on each side for 5 mins. Use a smaller lid to press them down until they are approximately 2cm thick. There will be a bit of sizzle as the water from the mushrooms reacts with the oil so just be careful here. Once the mushrooms are slightly golden on each side remove them from the pan and turn the heat off.
Marinate the mushrooms
Mix together the ingredients for the marinade. In a bowl or baking tray, marinate the mushrooms in the marinade ensuring that all the mushrooms are well coated. You can leave them to marinate overnight or for 20 mins. The longer you leave them soak the pinker and more flavourful they will be.
Cook the marinated mushrooms and slice
Heat the frying pan on high heat and add 1 tbsp of oil, remove the mushrooms from the marinade and fry them until they go a lovely charred colour on each side. This should take approx 2 mins on each side. See the picture below as a reference.
Remove the cooked mushrooms from the pan and slice them into 1cm thick slices.
Build your sandwich
Cut the baguette in half lengthwise. Add the mayo to the bottom and the pesto to the top. Slice the tomatoes and the gherkins. Add the lettuce on top of the mayo, followed by the tomatoes and the gherkins. Finally, add a generous amount of the mushrooms steak. Put the top on and cut in half for 2 amazing sandwiches!