Boil the potatoes in a well-seasoned pot of water   

While the potatoes are boiling, add the cashews, garlic, mustard and olive oil into a blender and blend. Add extra olive oil if the mixture is too thick.   

Roughly chop the herbs.   

Once the potatoes are boiled, drain and toss in a bowl with some olive oil. Add the cashew and oil mixture, and coat. Toss in the chopped herbs.   

Season to taste and garnish with some crushed red pepper and the lemon juice.