Cut the chicken: Slice each breast lengthways into strips about 2cm wide and 8cm long. Pat them dry with kitchen paper and season with salt and pepper.
Set up the coating station: Put the flour in a shallow bowl and season with salt and pepper. Beat the eggs with the soy sauce in a second shallow bowl. Mix the panko breadcrumbs with the dried thyme in a third bowl.
Coat the tenders: Take each strip and press it into the flour, shaking off any excess. Dip into the egg and soy mixture, letting any excess drip off. Press firmly into the panko, turning to coat all sides. Lay on a plate or board as you go.
Heat the oil: Pour a 2cm depth of vegetable oil into a large heavy-based frying pan and place over a medium-high heat. The oil is ready when a pinch of panko sizzles immediately on contact.
Fry in batches: Add the tenders in batches of 4 or 5, making sure they aren't touching. Fry for 3 to 4 minutes on each side until deep golden brown and cooked through.
Finish with butter: In the last minute of frying, add a knob of butter to the pan. It foams and helps the coating turn a deeper golden colour. Spoon the butter over the tenders as they finish.
Drain and serve: Move the tenders to a wire rack or kitchen paper. Serve hot with your choice of dipping sauce.
