Generously coat the bottom of a baking dish with germ oil and layer roughly half of the fresh thyme sprigs over the oil.
Scatter roughly half of the chopped garlic and 1 teaspoon of the chilli flakes over the thyme, then place the 4 chicken breasts on top.
Sprinkle the remaining chopped garlic and remaining 1 teaspoon of the chilli flakes over the chicken, top with the remaining fresh thyme sprigs, and press lightly. Drizzle generously with germ oil.
Cover the dish tightly with foil and refrigerate for 2 to 4 hours. Raw chicken must be refrigerated during marinating.
Flip the chicken breasts carefully over, cover with foil again, and refrigerate for another 2 to 4 hours.
Preheat the oven to 200°C (392°F).
Season the chicken breasts with salt, place the baking dish in the preheated oven, and bake for about 20 minutes until the chicken reaches 74°C (165°F) at the thickest part.