Preheat the oven to 200°C. Get out a large baking dish.
To make the glaze, brown the butter and add sage leaves once the butter is fragrant and caramelised and fry until crispy. (see video) When the sage leaves are crispy, remove and set aside.
Place the browned butter into the Thermomix. Add mustard, honey and salt. Cook 2 min/80°C/speed 2.
Mix 10 sec/speed 6. Set aside.
To assemble the tray bake, Brush a little glaze on the bottom of your tray. Add chicken pieces and brush with glaze and sprinkle with salt flakes. Add pumpkin, cauliflower, red onion, garlic and tomatoes. Pour stock over everything. Drizzle with any remaining glaze. Cover with foil and bake for 40 minutes. Remove foil and bake a further 30-40 minutes. Squeeze garlic out of the skins. Add crispy sage leaves before serving.