Preheat your oven to 200 °C (about 400 °F), static mode.
Choose medium-sized potatoes of similar size. Wash and then peel them with a peeler or a knife.
Cut potatoes into about 3 cm cubes.
On a cutting board, finely chop sage and rosemary, and mince garlic, with the core removed.
Add the potatoes in a large bowl, and add the oil, water, herb mixture, garlic and a good pinch of salt and black pepper. Toss to coat.
Transfer potatoes to a baking sheet lined with parchment paper and bake for 20 minutes.
Meanwhile, cut the sausage into large pieces, about 4 cm each.
After 20 minutes of baking, take the potatoes out of the oven and turn each piece over.
Add the sausage and bake for another 20 minutes at 200 °C (about 400 °F), turning the sausages halfway through.
By now, both the potatoes and sausage should be nicely browned. If you like, turn on the grill function and cook for another 4–5 minutes to create a nice crust on top.
Remove from the oven and serve immediately!