Preheat the oven to 170 degrees celsius. Lightly grease and line with baking paper a 22cm x 22cm baking tin, leaving a little extra paper hanging over the edge so you can easily remove the slice from the tin.
Sift the flour and mixed spice into a large bowl. Add the oats, ground almonds, brown sugar, coconut, pepitas, sunflower seeds, chia seeds and slivered almonds and mix well.
Put the butter and golden syrup into a saucepan and stir over a low heat until melted.
Remove from the heat and stir in the peanut butter and vanilla until combined.
Pour the butter mixture into the bowl of dry ingredients and mix with a large metal spoon until well combined.
Tip the mixture into the prepared tin, spread evenly, then press down very firmly. Bake for 20 minutes or until golden and firm.
Cool in the tin, then remove and cut into squares. Store in an airtight container.
Recipe by Villiers Brown at https://villiersbrown.com/muesli-bars/