Heat oven to 350°F. Lightly grease a 2 quart casserole dish.
Make filling
Add 8 peaches (peeled and thinly sliced), 3 tablespoons brown sugar, 3 tablespoon white sugar, 1 tablespoon cornstarch, 1 teaspoon lemon juice, ¼ teaspoon ground cinnamon and ⅛ teaspoon ground nutmeg to prepared casserole dish. Stir well to coat evenly. Place in hot oven and bake at 350°F for 20-25 minutes, stirring once halfway through, until peaches are soft and juices are bubbly.
Make topping
Combine dry ingredients: While peaches are baking, make topping. Combine 1 cup all-purpose flour, 3 tablespoons white sugar, 3 tablespoons brown sugar, 1 teaspoon baking powder, ¼ teaspoon baking soda and ¼ teaspoon salt in large mixing bowl.
Mix in butter and liquids: Add cold butter to flour mixture, use a pastry cutter or clean hands to rub butter into flour until mixture resembles crumbs. Stir through buttermilk, combining only until all dry ingredients are moistened. Batter will be thick and lumpy.
Assemble and bake cobbler
Assemble: Drop batter by the tablespoon over peach filling, leaving gaps in between to let steam escape. Sprinkle with sugar, if desired.
Bake: Bake cobbler for 20-25 minutes at 350°F, until topping is baked through and golden on top.
Cool: Allow cobbler to cool on cooling rack for 20 minutes to allow juices to thicken. Serve warm.
Notes
Ingredient notes
Peaches: I like fresh best, but frozen or canned are fine, too.
Buttermilk: Don’t have buttermilk on hand? Use regular milk and stir in 1 teaspoon of white distilled vinegar. Let stand for 5 minutes, then use in the recipe.
Butter: Use unsalted butter, cold from the fridge. If you prefer using margarine, please use stick margarine intended for baking and not a buttery spread!
Recipe tips
Mixing: Don’t overmix the topping, or it may come out dense! Combine the crumb mixture with the buttermilk just until all of the ingredients have been moistened – the batter will be thick and lumpy, that’s exactly how it should be!
Filling consistency: Everything depends on your exact peaches when it comes to the filling! The ripeness/sweetness, firmness and juiciness dictate if you need to adjust anything. Once the filling is ready, taste a little (careful, hot!) and adjust if needed:
More lemon juice or a spoonful of water if the peaches are not releasing any juices/the filling is too dry
Cornstarch slurry (combine 1 teaspoon cornstarch with 1 teaspoon cold water, quickly stir into the filling juices) if the filling is very soupy/liquidy
Additional sugar if the filling is too tart
Additional lemon juice if the filling is too sweet
Assembly: Make sure to drop the topping in spoonfuls over the filling, do not spread it out! You need the gaps in between for the steam to escape, otherwise your topping may not fully bake.
Store leftovers covered on the counter for up to a day, or covered in the fridge for up to 3 days.