Step 1

Preheat oven to 200C/390F.

Step 2

Brush a 12 hole, standard muffin tin with melted butter, or line with paper cases. (Note 3)

Step 3

Place butter and brown sugar in a bowl, whisk to combine.

Step 4

Add milk, then egg and vinegar. Whisk to combine.

Step 5

Scatter flour across batter surface, followed by baking soda, cinnamon and salt. Whisk 10 times until the flour is incorporated - some lumps is fine.

Step 6

Stir through apple -minimum stirs just to disperse.

Step 7

Scoop batter into muffin tin - I use an ice cream scoop - filling it all the way to the top. If using a scooper, leave it the slight ball shape (see video) - don't smooth the top.  You should get 12 (see Note 3).

Step 8

Sprinkle with sugar (if using - makes surface slightly crispy), place muffins in the oven.

Step 9

Immediately turn down to 180C/350F.

Step 10

Bake for 20 minutes (standard) or 18 minutes (fan / convection) , or until a skewer comes out clean.

Step 11

Rest in the muffin tin for 5 minutes then transfer to a rack to cool.

Step 12

Once fully cooled, store in an airtight container - it will stay moist for up to 5 days. These also freeze very well.