Place a medium non-stick frying pan over high heat. Add the oil, garlic and diced mushrooms and saute until the mushrooms are crunchy. They will be about a quarter of the volume of the fresh ingredients.
Place into a large mixing bowl and cool slightly.
To the bowl, add the ground turkey, sage, salt, pepper, and egg. Mix well.
Split the mixture into 4 and use a burger press to make evenly sized patties.
In a large frying pan, add the remaining oil and saute the burgers for 3-4 minutes in each side until cooked through.
Before removing the burgers from the heat, add 2 slices of swiss cheese to the top of each and allow to melt before removing from the heat.
Add the sliced mushrooms straight into the pan that the burgers were cooked in, season, and saute until soft.
To serve, place 1 or 2 lettuce leaves onto your plate as the base “bun”, add a quarter of the arugula, then top with a burger and some mushrooms. Drizzle over the aioli and top with another 1-2 lettuce leaves and enjoy immediately!