01 -
Heat oven to 190°C / 375°F. Line a standard 12-cup muffin pan. Cut peeled apple into small 5–7 mm dice and chop walnuts.
02 -
Whisk flour, sugar, baking powder, cinnamon, nutmeg and salt together, breaking up any sugar lumps.
03 -
In a second bowl whisk eggs, milk, oil and vanilla until smooth.
04 -
Pour wet ingredients into the dry mixture. Fold gently until almost combined, then fold in apple and walnuts just until no pockets of flour remain. Do not beat the batter smooth.
05 -
Divide evenly among the 12 cups, filling each about three-quarters full. Bake 20–25 minutes until risen and a skewer inserted in the crumb comes out without wet batter.
06 -
Cool in the pan for 5 minutes, then transfer to a rack for 10 minutes. Break one open after cooling to see tender crumb with small apple pieces and chopped walnuts.
07 -
Cool completely before storing. Keep covered in the refrigerator for up to four days, or freeze for up to two months. Bring to room temperature or warm briefly before serving.