Boil the potatoes until fork tender
Heat a drizzle of olive oil in a large pan on high heat. Slice and cook the mushrooms until browned, then set aside to cool
Once the potatoes are softened, place into a cake or quiche tin and use the bottom of a glass to squish them into the base
Spray generously with olive oil and bake in the oven for 30 minutes or until browned and crispy. Set aside to cool slightly
In a large bowl, combine the eggs, milk, yoghurt and whisk well
Add the sliced spring onions, grated cheese, cooked mushrooms, sliced ham (reserving some for on top) and mix until combined
Season with salt and pepper
Pour the egg mixture into the tin. Top with remaining ingredients and place back in the oven for 45-50 minutes or until set
Allow to cool slightly before slicing and serving
