In a skillet, heat the olive oil and butter over medium heat. Add the chopped onions and garlic, sauté until translucent. Add the chopped mushrooms, thyme, salt, and black pepper. Cook until the mushrooms are soft and excess moisture has evaporated. Remove from heat and stir in breadcrumbs and Parmesan cheese. Let the mixture cool slightly.

Stuff the Quail

Preheat the oven to 180°C (350°F). Gently loosen the skin of the quail and stuff each bird with the mushroom mixture. Season the outside of the quail with salt and pepper.

Roast the Quail

Place the stuffed quail on a baking tray and roast in the preheated oven for about 25-30 minutes, or until the quail is cooked through and golden brown.

Prepare Dirty Potato Salad

While the quail is roasting, prepare the dirty potato salad by boiling potatoes until fork-tender, then chopping them. Toss with olive oil, vinegar, diced celery, green onions, and season with salt and pepper to taste.

Grill Frisee

In a separate skillet or grill pan, lightly char the frisee until slightly wilted. Drizzle with olive oil and season with salt.

Serve

On a plate, serve a generous scoop of dirty potato salad topped with the roasted mushroom stuffed quail and grilled frisee on the side.