Gather and prepare your ingredients.
Line a 12 x 22 x 6cm loaf tin with parchment paper.
Place the flour, oats, seeds and salt into a large bowl and mix to combine.
Place the water, yeast and maple syrup into a jug and whisk to break up the yeast. Pour the liquid into the dry ingredients, and stir to combine. The mixture will be quite wet and sloppy at this stage.
Scrape into the prepared loaf tin. Dip a spoon into water and use this to smooth out the surface.
Set aside to prove overnight, or for at least six hours.As this is a dense loaf the rise will not be dramatic, but it should be slightly puffier. If you poke it with your finger and an indentation remains, it’s ready for the oven.
Heat the oven to 220°C / 200°C fan. Bake for 55-60 minutes until darkened. To test readiness, remove the loaf from the tin and knock it gently on the bottom, it should sound hollow. Allow to cool completely before slicing.