1. Set the oven on dry heat at 260°C. 2. Submerge the potatoes in water and insert the core probe in the water, set to 65°C. 3. Meanwhile submerge enough potato skin in milk in an ovenproof dish. 4. When the water reaches the desired temperature, set the oven on steam at 65°C. 5. Leave the potatoes in there, but also putting the milk and potato skin in the oven. 6. Cook for 20 minutes. 7. Drain the potatoes. 8. Drain the skin, reserving the milk and throwing away the skin. 9. Leave the potatoes outside on a perforated dish for 15–20 minutes so they can let out steam. 10. Set the oven back on dry heat at 260°C. 11. Submerge the potatoes in water again and insert the core probe just as before, this time setting its temperature to 100°C. 12. Once the water reaches its desired temperature, set the oven on steam at 100°C and cook until tender. 13. Drain and mash using a ricer, while the spuds are still steaming hot. 14. Melt in the butter and stir with a maryse. 15. Add enough potato milk to correct the texture. 16. Season and serve Preparation for the gravy: 1. In a large saucepan, soften the onions over medium heat with the star anise, leaving the spice whole. 2. Keep going for a good 10–15 minutes and deglaze with red wine, cranking up the heat to let the alcohol evaporate. 3. Add the stock and lower the heat as soon as it starts showing signs of boiling. 4. Reduce for a few hours, stirring from time to time, until the consistency reaches a beautiful, glazed, gravy-like texture. Serve by spooning a generous portion of mash onto a plate, placing two sausages over the potatoes and ladling some onion gravy on top to finish.