Preheat your oven to fan-assisted 160C / 180C / 350F /gas 4 and prepare your muffin tin.
Combine the polenta, flour, orange zest, lemon zest, baking powder, sodium bicarbonate and salt in a large bowl and set aside.
In a separate bowl, whisk together milk, orange juice, olive oil and maple syrup.
Pour the wet ingredients into dry ingredients and mix until combined.
Pour the muffin batter into the muffin tin and top with blood orange slices bake for 20 – 25 minutes in the preheated oven, or until a skewer inserted into the centre of a muffin comes out clean.
Remove the muffins from the oven and let it cool before serving.