Preheat the oven to 180C/350F.
Add the cubed bread to a large, lined baking tray. Melt the 140 grams of butter, pour it over the bread cubes, and bake until golden brown, about 20 minutes.
While the bread is browning, add the remaining 70 grams of butter to a nonstick pan and sauté the onions and celery (with the bay leaf if you are using) until translucent and soft. Add the apples and herbs and cook for another minute or two. Decant into a large bowl (remove the bay leaf).
In the same pan, add the pork sausage meat, breaking it up with a spatula or masher, and sauté until it starts to turn golden. Add the meat to the bowl with the vegetables.
When the bread cubes come out of the oven, add them to the bowl too.
Add the vegetable stock cube to the hot chicken stock, pour over the stock, and give it a good mix to combine.
Butter a large casserole dish with Kerrygold salted butter and decant the stuffing into the dish. Cover the dish with tin foil and bake for 30 minutes. Remove the foil and bake for a further 15 – 20 minutes until golden brown (if you want to speed this up, you can put it under the grill for a few minutes until golden).
While the casserole is baking, heat the remaining butter in a small pan and fry a handful of sage leaves until they start to sizzle, remove and set aside. Allow the brown butter to cool and settle.
When the casserole comes out of the oven, scatter over the crispy sage leaves and drizzle over the brown butter.