Pre-heat oven to 220 degrees celsius (fan-forced).
Sift flour into large mixing bowl. Add sugar and poppy seeds and stir to combine.
Add remaining ingredients, apart from the marmalade, and stir gently to combine. Don't over-stir.
Prepare muffin tin by greasing well or spraying with oil. If you have the large cafe-style muffin tin, this mixture makes 6 muffins. If you have a cupcake-size tin, it makes 12 muffins.
Spoon mixture into tins. If desired, sprinkle a small amount of poppy seeds on each muffin, with the optional extra poppy seeds, and place into oven.
Cook for 5 minutes before turning oven temperature down to 190 degrees celsius (fan-forced). If you're using a smaller cupcake tin, bake for a further 10-12 minutes (or until a metal skewer inserted into a muffin comes out clean). If using a cafe-style larger muffin tin, bake for a further 18 minutes (or until a metal skewer inserted into a muffin comes out clean).
Remove from oven and use a brush to glaze the muffins with marmalade. You may need to heat your marmalade a little in the microwave first to make it runny and also use kitchen scissors to chop any larger pieces of rind, depending on the style of marmalade.
Allow to cool for a few minutes before easing each muffin from the tin and placing on a cooling rack.