In a large mixing bowl add the white sugar, sourdough discard, sour cream, milk, vanilla extract, avocado oil, melted butter, and eggs. Whisk ingredients together until blended.
1 (200g) cup granulated white sugar, ½ (120g) cup sourdough discard , ½ (120g) cup full-fat sour cream , ⅔ (150g) cup whole milk , 4 (60g) Tbsp unsalted butter, ¼ (60g) cup avocado oil , 2 eggs, 2 tsp vanilla extract
In a separate bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt.
3¼ (400g) cups all-purpose flour, 2½ tsp baking powder, ½ tsp baking soda, ¾ tsp fine sea salt, ¼ tsp ground cinnamon
Add the dry ingredients to the wet, whisking together until no streaks remain. It's important to not overmix the batter, as this will make the muffin tough.
Overnight Ferment Option: At this point you have the choice to ferment the batter overnight. If you choose to ferment, cover the bowl with plastic and transfer to the refrigerator overnight. If your batter was fermenting in the refrigerator overnight, allow to rest at room temperature for an hour the next day to warm up. You can skip this step if you are not fermenting the batter.
Gather your peaches, and wash and peel the skins if desired. Chop your peaches into roughly 1/4 inch cubes.
1¾ (250g) cups fresh peaches
You don't want these peach pieces too small or you won't taste them, but you also don't want them too large or they won't mix properly. The key is even chunks.
Toss the peaches in flour to coat them, then add them to the muffin batter. Gently fold the muffin batter to distribute the peaches evenly throughout, but avoid overmixing the batter.
1 (8g) Tbsp all-purpose flour