Flatten the chicken between greaseproof paper using a rolling pin until 1cm thick.
Blend hazelnuts, parmesan, lemon zest, and thyme in a food processor into fine crumbs.
Add panko breadcrumbs to the processor and pulse briefly to combine.
Season flour with salt and pepper on a plate and dust the chicken breasts thoroughly.
Dip chicken into beaten eggs and then coat firmly with the hazelnut crumb mixture.
Fry chicken in melted butter for five minutes per side until golden-brown while basting.
Drain chicken on kitchen paper and sprinkle with extra parmesan cheese.
Serve the chicken drizzled with pan butter and a squeeze of lemon juice.
Garnish the plate with salad leaves and a lemon wedge.