Soak raw cashews overnight or in boiling hot water for at least 1 hour.
Preheat the oven to 180 Celsius and line a baking tray with baking paper.
Season mushrooms and roast in the oven for 25-30 minutes or until mushrooms are tender.
While the mushrooms are roasting in the oven, prepare the pesto and other ingredients.
To make the pesto, in a food processor or a blender, blend all the ingredients for the pesto until smooth and creamy.
Slice sourdough English muffins into half and toast up in a pan or a griller with some olive oil.
Remove mushrooms from the oven and allow cool down slightly before handling.
To assemble the breakfast muffins, spread 1-2 tbsp pesto onto both muffins and layer roasted mushrooms, sliced tomatoes and a handful of fresh rocket leaves onto one muffin and finally cover the other half muffin on top.