In a medium bowl, beat the butter with a wooden spoon until it is soft and creamy. Add the rest of the ingredients and mix well. Place the butter mass onto a piece of parchment paper or cling film and shape into a log. Twist the ends and refrigerate until firm.
For pancakes:
Place the flour, baking powder, whole egg, butter, salt, cumin and milk in a large mixing bowl and mix until smooth. Add the spring onions, chillies and spinach and mix until well combined.
Whisk the egg white to soft peaks and gently fold into the batter.
Add a 1/2 tablespoon of olive oil to a heavy frying pan and place on medium-high heat. Ladle 2 tablespoons of batter for each pancake. Cook for about 2 minutes on each side, or until they are golden on each side. Keep the cooked pancakes in a warm oven until all the pancakes are cooked.
To serve, place three pancakes on a plate and place a slice of the lime butter on top.