Start by preparing the pancake batter; sifting the flour with a pinch of salt into a mixing bowl. Add the egg and half of the milk and whisk, starting slowly, until you have a smooth, thick batter. Whisk in the rest of the milk until you have the right consistency. Add teaspoons of the melted butter to a small frying pan and heat over a medium heat.
Fry the pancake batter, 2 tbsp per pancake, making sure you tilt the pan to coat the surface as soon as you have added the batter. Keep the cooked pancakes warm on a plate lined with aluminium foil that is big enough to wrap over the pancakes and cover them loosely. Preheat the oven to 180°C.
Loosen the fromage frais with a whisk in a mixing bowl, then fold through the chopped chives and some seasoning. Brush the asparagus spears the olive oil and season generously. Lay the pancakes on a flat surface and spread evenly with the Dijon mustard. Follow with a slice or two of ham on top of the mustard. Spoon half of the fromage frais mixture on top then arrange the asparagus spears on top and spoon the remaining fromage fraise on top.
Roll the pancakes up by the sides over the filling then arrange with the seam side down on a lined baking tray. Bake for 8-10 minutes until the asparagus is tender. Remove and arrange on serving plates, garnished with a couple of chive stems.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.