Clean the shiitake mushrooms by removing stems and rinsing gently under water. Pat dry with paper towels.

Dice the carrot, zucchini, and onion into small pieces.

Preheat the oven to 170°C (338°F) for 30 minutes with both top and bottom heat settings.

Heat a frying pan with a small amount of cooking oil and sauté the diced vegetables until softened.

Add the cooked mixed rice to the pan and stir well with the vegetables.

Season the rice mixture with 2 tbsp soy sauce, stirring until evenly coated.

Place a small amount of butter in the center of each shiitake mushroom cap.

Arrange the mushrooms on a baking tray lined with parchment paper and bake at 170°C for 15 minutes.

Fill each baked mushroom cap with the prepared vegetable fried rice.

Heat a frying pan with a small amount of cooking oil and fry quail eggs sunny-side up, keeping the yolks runny.