First make the raspberry compote: tip the raspberries into a medium-sized saucepan. Add the caster sugar, lemon zest and 1 tbsp water. Place over low-medium heat and slowly bring to the boil, stirring occasionally until the sugar dissolves. Once simmering, reduce the heat and cook gently for about 5 minutes - or until the raspberries have collapsed. Remove the raspberries from the heat and add lemon juice, to taste. Adjust the sweetness, if necessary. Pour into a bowl and set aside.
Next, make the pannekaken: pour the milk into a blender and add the eggs, followed by the flour, sugar and salt. Blitz until you have a smooth batter. Alternatively, whisk everything together in a large mixing bowl until completely smooth - you may find it easier to sieve in the flour.
Grease a large non-stick crepe or frying pan with butter and place over medium-high heat. Once hot, add a small ladleful of batter to the pan, tilting and swirling to ensure it evenly coats the base in a thin layer. Cook for about 30 seconds - or until the top has just set. The exact time will depend on the size of your pan, the heat of your hob and how thick your batter is. Once set, carefully flip the pancake over - you may find it easier to loosen it with a palette knife or spatula first. Continue to cook for a further 10 seconds on the other side - or until lightly golden. Slide onto a plate and cover loosely with foil to keep warm. Repeat with the remaining batter, greasing with more butter if necessary, until you have around 6 pannekaken.
Serve the pannekaken warm with the raspberry compote, whipped cream, a dusting of icing sugar and sprigs of fresh mint.