Preheat your oven to 180°C / 350°F (160°C fan). Spread pecans on a baking tray and toast for 5 minutes. Cool slightly, then finely chop.
Turn the oven up to 200°C / 390°F (180°C fan). Line your muffin tin with paper liners.
Make the crumble: mix flour, brown sugar, salt, and chopped pecans in a small bowl. Add melted vegan butter and mix with a fork until it looks like wet sand. Set aside.
Make your flax egg: combine 1 tbsp ground flaxseed with 3 tbsp water and rest for 5 minutes until gelatinous.
Whisk all dry ingredients together in a large bowl.
Whisk all wet ingredients together in a separate bowl until smooth.
Pour wet into dry and fold with a rubber spatula — about 14 folds. The batter will be lumpy. That's correct. Lumpy batter = fluffy muffins.
Fold in the 1¼ cups peach pieces. Stir just until you can't see flour. Minimum stirs. Seriously.
Fill the muffin tin quickly — divide batter evenly, filling holes to the top. Press extra peach pieces on top of each, then pile the crumble on generously.
Bake 23–25 minutes until a toothpick comes out clean. Rest in the tin for 10 minutes, then transfer to a rack — or eat one immediately. I won't judge.
Speed note: Once the batter is mixed, baking soda is already activated. Get those muffins into the oven within 5 minutes or they'll lose their rise.
