Heat your oven to 200°C (180°C fan).
Line your muffin tin with paper cases.
This prevents sticking and makes cleanup easy.
Put flour in your large bowl.
Add sugar, baking powder, and mixed spice.
Mix everything together with a spoon.
Make sure there are no lumps.
Crack eggs into your medium bowl.
Add oil and milk to the eggs.
Whisk them together until well combined.
The mixture should look smooth and even.
Pour wet ingredients into dry ingredients.
Stir gently until just combined.
Don't overmix or muffins become tough.
Add mincemeat and walnuts now.
Fold them in carefully.
Spoon mixture into muffin cases evenly.
Fill each case about three-quarters full.
Bake for 18-20 minutes.
They're done when golden brown.
Remove muffins from the oven carefully.
Let them cool for 5 minutes.
Transfer to a wire rack.
Dust with icing sugar before serving.