Use free range eggs with this frittata, they have a lot more flavour. You finish this in the oven or under the grill so you need a frypan with a heatproof handle.
Whisk the eggs and cream together. Add the smoked salmon, asparagus, parmesan and dill. Season and mix well.
Heat the butter and olive oil in an oven-safe frying pan. Pour in the egg mixture and cook over a low heat until the bottom has set. Finish off the cooking by placing the pan in the oven for 15-20 minutes, or until just set. You can also do this under the grill.