Split half a dozen asparagus spears in half lengthways and blanche in boiling water for 30 seconds, then drain and cool under running water and set aside.
In a small saucepan, melt most of the butter with a dash of olive oil and cook the mushrooms on a high heat, season with pepper. Once cooked, remove from heat and cover.
In a bowl, whisk the eggs and cream until combined. Heat a 20cm frying pan on a high heat and melt the remaining butter. Pour in the egg mix and turn the heat down to medium. Without using utensils, move the liquid egg mix gently around the pan until almost all liquids are cooked. Place the asparagus spears over one half of the omelette.
Use the tip of a knife to release the omelette from the other side of the pan and flip this half of the omelette over the asparagus and serve immediately.
Serve with toasted sourdough, mushrooms and sprinkle with chopped chives.