Preheat the oven to 200C / 392F
Prepare the chicken by removing excess fat around the cavity, washing inside and out and patting dry with paper towel. Season inside and out with salt and pepper.
Combine the herb butter ingredients. Using your hands, starting at the cavity, gently put your hand under the skin pushing the butter up as far as you can go and spreading it around. Be careful not to break the skin.
Prepare the stuffing. In a large frying pan, add the butter and garlic paste and put over medium heat. Once the butter has melted, add the onion and saute until the onion is translucent.
Add the mushrooms and cook through. Place the mushrooms in a mixing bowl, keeping any butter in the pan.
Add the diced bacon and pecans and turn the heat to medium-high, cooking until the bacon is crispy and pecans lightly browned.
Add the spices and stir to combine, cook for 30 seconds. Add the bacon and pecans to the bowl with the mushrooms, along with the almond meal and egg and stir to combine.
Depending on the water content of your mushrooms and bacon, you should need about 2 - 3 tablespoons of almond meal until it is just holding together.
Stuff the chicken cavity with the mixture once cool enough to handle. Tie the legs with kitchen twine to help keep the stuffing in.
Place the chicken, breast side up on a roasting tray with wire rack.
Roast for 1 hour and 15 minutes, or approx 30 minutes per 500 grams for a bigger chicken.
Check doneness with a thermometer inserted into 2 - 3 different point on the bird, including in the stuffing. You want a temperature of 75 degrees c.
Remove from the oven and tent with foil, resting for 5 minutes before carving.