Mix Crumble ingredients. Whisk Dry and Wet ingredients in separate bowls, mix together, stir in peaches. Fill muffin tin, top with extra peaches, top with Crumble. Bake 200°C / 390°F (180°C fan) 23 - 25 minutes.
Preheat oven to 180°C / 350°F (160°C fan-forced).
Toast pecans - Spread the pecans on a tray and place in the oven for 5 minutes. Remove, cool slightly then finely chop.
Turn oven up to 200°C / 390°F (180°C fan-forced). Line a 12 hole standard muffin tin with paper liners.
Crumbly topping - Mix the flour, sugar, salt and chopped pecans using a fork in a small bowl. Add butter and mix until it resembles wet sand. Set aside.
Muffin batter - Whisk the Dry ingredients in a large bowl. Whisk the Wet ingredients in a separate bowl. Pour the Wet into the Dry ingredients bowl then mix with a rubber spatula until the flour is almost incorporated - about 14 stirs, the batter will be lumpy.
Add peaches - Add the 1 ½ cups peach pieces, then mix just until you can no longer see flour and the peaches are dispersed. Minimum stirs is key here, for soft muffins!
Fill muffin tin - Working quickly (Note 4), divide the batter between the holes, filling to the top - a lever ice cream scoop is super useful here! Lightly press the Extra peaches on top of each muffin, then spoon the Crumble on - just pile it on top and use it all!
Bake 23 - 25 minutes (check first at 23 minutes), until a toothpick comes out clean. Leave in the muffin tin for 10 minutes then transfer to fully cool on a rack - or eat!
