Gut, flay and skin the quails, remove the breasts and throats. Season with salt and pepper.
Heat the butter, brown the finely chopped poultry bones, add the coarsely diced vegetables and the plucked rosemary, extinguish with white wine and cook. Add stock and jus and reduce to desired consistency, season, strain and beat in a hand mixer.
Peel the potatoes and cut into thin slices with a slicer. Spread out on a dish rack into 8 equal squares, overlapping each potato slice by 1/4, season sparingly with salt and season with pepper.
Brush the potatoes with beaten egg yolk, and carefully wrap one breast and leg at a time in the potato mat. In a frying pan, cream the butter, add the plucked rosemary and bake the quail breasts over medium heat until golden brown.
