Step 1Heat the oven to 325 degrees.
Step 2Cook the juice from the peaches in a heavy pot over medium heat until thickened to heavy syrup, 10 to 12 minutes. Pour the syrup into the bottom of an 11x7-inch baking pan. Add the 1/4 cup honey. Dot with the butter and arrange a thick layer of peaches over the top.
Step 3Beat the eggs yolks until thick and lemon-colored, 4 to 6 minutes. Gradually add the 2/3 cup honey, beating constantly. Add the lemon juice and blend. Add the hot water and beat hard for 3 minutes.
Step 4Sift together the flour, baking powder and salt and stir into the egg mixture.
Step 5Beat the egg whites until stiff, 3 minutes, and fold into the mixture. Pour the batter over the peaches and smooth with an offset spatula. Bake the cake until it's firm on top and golden brown and a toothpick inserted in the middle comes out clean, 30 to 35 minutes. Cut it into pieces and serve with whipped cream.
Step 1Beat the cream, sugar and vanilla together until firm, 3 to 5 minutes.