Preheat the oven to 170C/325F/Gas 3. Line two large roasting trays with parchment paper and set aside.
Put the maple syrup, sugar, oil and vanilla extract into a large bowl and mix well.
Then toss in the oats, mixed seeds, pecans and salt and cinnamon (if using). Give it a good stir and then get your hands in, picking it up and letting it fall down to coat and moisten everything really well.
Pour the mixture onto the roasting trays and spread it out evenly.
Bake in the oven for about 15 minutes, giving it a good stir and swapping them about on their shelves half way through.
The granola should be golden-brown when cooked. Remove and leave to cool completely before stirring the cranberries through. Store in an airtight container for up to a month.