Add the olive oil and butter to a pan and melt. This can be either done on a hob or on your Big Green Egg.
Slice your bacon into small pieces and add it together with the chopped onion to the melted butter and oil. Cook on the Egg for about 8-10 minutes until the onions have softened.
While the onions are softening, place the slices of bread into a mixer and blitz into breadcrumbs.
Now chop the chestnuts into chunks. I don't like them too fine.
Once the onions have softened, take the pan from the Egg and add the chestnuts, breadcrumbs and a pinch of cumin seeds. Mix well.
Transfer the mixture to a heat proof ceramic dish.
Set up your Egg for an indirect cook with the ConvEGGtor feet up with the stainless grid on top. Set the Egg to 180°C.
Place the dish of stuffing into the Egg and cook for about 30 minutes.