Heat oven to 375 degrees. Grease 13x9 pan.
Wash and cut peaches into 6 wedges. Place in 13x9 pan and toss with 1/2 c. sugar, lemon juice and zest, small pinch of salt between two fingers, and 1/4 c. flour.
In medium bowl use fork to whisk 1/4 c. sugar, egg, vanilla and buttermilk. Set aside.
In mixer bowl combine 1 1/2 c. flour, baking powder and salt. Cut butter in 1/4" thick chunks into bowl and mix for approx. 1 minute. Should look like chunky sand.
5 Pour egg mixture into bowl and mix just until combined. (Some butter will still be visible in small chunks.)
Spoon batter over fruit and sprinkle lightly with sugar. Bake 40-45 minutes. Topping should be light golden brown and liquid bubbly.
Top with whipped cream or vanilla ice cream.
According to http://www.fruitsandveggiesmorematters.org/?page_id=186 , one medium peach provides 15% of RDA for vitamin C, as well as a good amount of vitamin A and fiber. Store them in a paper bag if they need to ripen when you buy them.