Step 1

Heat the oven to 350°F (175°C), with a rack in the center. Line a large rimmed baking sheet with aluminum foil or parchment paper.

Step 2

Arrange the peaches in a 9 by 13-inch (23 by 33cm) or two 10-inch pie plates or other similar-size baking pan or gratin dish. Using a zester or Microplane, zest about 2 teaspoons of lemon zest evenly over the fruit. Cut the lemon in half and squeeze about 1⁄4 cup (60g) of lemon juice over the top.

Step 3

In a stand mixer fitted with the paddle attachment, cream the butter and 1 1/2 cups (300g) of the sugar on medium speed until creamy but sandy, about 1 minute. Add the flour, baking powder, and salt and beat on medium speed until all the flour is incorporated and the mixture is evenly crumbly, about 30 seconds more. Scrape down the sides of the bowl. With the mixer on low speed, slowly pour in the milk. Increase the speed to medium and beat until the batter is light and fluffy, about 2 minutes.

Step 4

Scoop the batter in about 6 large blobs over the peaches. With an offset spatula or the back of a big spoon, carefully spread the batter evenly over the fruit.

Step 5

Sprinkle the remaining 1/2 cup (100g) sugar over the batter. Drizzle the hot water evenly over the sugar, using it to melt the sugar topping.

Step 6

Set the pan on the foil-lined baking sheet and bake the cobbler until the top is golden brown and cracked, 70 to 80 minutes. A toothpick stuck in the topping should come out clean or with just crumbs clinging—be sure to check in a few places.

Step 7

Let the cobbler cool for about 30 minutes to firm up. Serve warm, scooping it into big bowls and pouring a little heavy cream over the top. Refrigerate any leftovers airtight.