Wash leeks well, dry and cut in half lengthwise. Form small pockets from aluminum foil and place the leeks inside. Drizzle with olive oil and season with salt and pepper.
Close pockets and braise in preheated oven at 230 °C for 15 minutes.
Open and finish braising for another 5 minutes.
For the dip, mix all ingredients together well and season with salt and pepper.
Dress and sprinkle with fresh lemon thyme and serve.