Boil the quail eggs in a pan of boiling water for 2 minutes. Then plunge into an ice bath – this will stop them cooking further and ensure you have a runny yolk at the end.
While they are cooling, make your Mayo.
Place 2 egg yolks in a large bowl. Add the mustard and vinegar and whisk them well until they are paler. Slowly drizzle in the oil in a steady stream, whisking continuously – this will emulsify the egg yolk and it will thicken and become glossy. Keep slowly adding until you have added 1/2 the oil.
At this stage squeeze in juice of 1/2 a lemon. Then drizzle in remaining oil, whisking continuously until all is added. Season the mayonnaise with the chopped tarragon, salt and some more lemon or mustard to taste. Set aside.
Peel the quail eggs carefully as they are delicate. It is quite therapeutic and satisfying!
Time to assemble. Add fresh chopped thyme to your sausage meat. Season the plain flour well with salt and pepper. Place a small amount in the palm of your hand and press to flatten, place a quail egg in the middle and cup your hand to enclose the egg in the meat. Gently press the sausage meat around the egg so it is completely covered and there are no air pockets.
Next place the egg into the flour and coat, then dust off the excess. Do the same in the egg, and then followed by the panko. Repeat with all the quail eggs.
Heat vegetable oil in a high sided pan so it comes up 2 inches high. Heat until it reaches 180C.
Fry the scotch eggs in batches for 2 minutes until golden brown on all sides and crisp. Remove carefully with a slotted spoon and drain on kitchen paper to remove excess oil.
Serve alongside the tarragon mayo!