Buttermilk Sheet Cake With Peaches and Blueberries
Serves 15 to 20.
Note: If you don't have a stand mixer, a hand mixer and a large bowl will work just as well. To peel peaches, plunge them it into boiling water for 30 to 45 seconds, then use a slotted spoon to transfer them to a bowl of ice water. As soon as they are cool enough to handle, slip off the skins. The riper the peach, the less time it needs in the boiling water.
• 16 tbsp. (2 sticks; 226 g; 2 sticks) unsalted butter, at room temperature, plus more for the pan
• 3 c. (360 g) flour
• 1/2 tsp. (3 g) baking soda
• 1/2 tsp. (3 g) kosher salt or fine sea salt
• 2 c. (400 g) sugar
• 3 eggs, at room temperature