Wash spring onions and dry them. Cut off hairy part at the heads and then cut lengthwise.
In a large bowl mix eggs and milk together until well combined (I used an electric mixer) and then add the flour and salt and mix until the batter is smooth and no more lumps can be seen.
Once the oven has reached required heat remove pan and put it on stove, move around a little to evenly coat the bottom with the hot butter, add the batter and return into the oven for 20 minutes (set a timer!).
Heat a large pan on the stove over medium heat.
Add a splash of olive oil and once hot add spring onions in one layer. Leave alone for about 1 minute, then turn or stir until tender (in total about 10 minutes).
Grate Emmental cheese.
Once timer goes off, take dutch baby out of the oven immediately cover bottom with grated Emmental cheese, place onions and smoked salmon on top and sprinkle dill on all of it.