Preheat oven to 200°C bake / 180°C fan bake. Line a 12-hole muffin tin with paper cases (or grease well).
Cut feijoas in half, scoop out flesh with a spoon and roughly chop until you have 1 full cup (or 275g).
Melt butter in a large heatproof bowl. Stir in feijoas, eggs and Chelsea White Sugar.
Add flour, baking powder and milk and fold in until just combined. Divide mixture evenly between muffin tin holes.
Mix Chelsea Demerara Sugar and cinnamon together to make topping. Spoon over muffins.
Bake for 15-20 minutes, until muffins are golden and spring back when lightly pressed.
