1. Peel and pit peaches and slice into 1/2-inch-thick wedges, dropping slices into a shallow 2 1/2- to 3-quart oval or other baking dish. Gently mix in 1/3 cup sugar; taste, and add a little more sugar if desired.
2. In a bowl, beat butter and remaining 1/3 cup sugar until well blended. Stir in 1/3 cup milk.
3. In another bowl, mix 1 1/2 cups flour, baking powder, and salt. Add to butter mixture with another 1/3 cup milk and stir to combine. Batter should be stiff and sticky; if too dry, add a little more milk; if runny, add flour. Stir in vanilla.
4. Drop batter by tablespoonfuls evenly over prepared fruit (some fruit will show through).
5. Bake in a 350° oven until top is browned and fruit is bubbling, 35 to 40 minutes. Serve warm or at room temperature: scoop into bowls and drizzle cream over each serving if desired.