Heat the oven to 160°C (140° fan) 325°F gas 3. Grease a 900g|2lb loaf tin and line the base with non-stick baking paper.
Puree the beetroot with a handheld stick blender or in a blender.
Beat together the sugar, salt, butter and vanilla in a mixing bowl until light and creamy.
Add the eggs one at a time, beating well between each addition.
Fold in the flour, then stir in the creme fraiche and seeds, followed by the pureed beetroot.
Spoon into the tin and bake for 50-60 minutes until cooked through. Cover the top with foil if browning too much. Cool in the tin for 10 minutes, then place on a wire rack to cool completely.