In a saucepan, melt the butter and fry the onions and garlic for 4-5 minutes until softened.
Add the stock cube, sage, rosemary and the milk. Simmer until dissolved and the milk is warm.
Remove from the heat and add the breadcrumbs. Stir once or twice and let the milk absorb the breadcrumbs for a few minutes or until cold.
Transfer to a bowl, then add the sausage meat, cheddar, pepper and combine.
Use the mixture to create 8-12 balls, depending on the size you want. Place in the fridge until needed.
Place the stuffing balls in the air fryer basket. Roast for 10-12 minutes until coloured and cooked throughout, shaking if necessary halfway through the cooking.
Remove from the air fryer and keep warm until ready to serve.