Preheat the oven to 350 degrees. Smear the bottom of 9x13 pan with a little bit of butter. Add peaches and sugar, and mix directly in the pan. Mix the butter, sugar, vanilla, flour, baking powder, and salt until a cookie-dough-like batter forms. Place scoops of the mixture over the top of the peaches. Spread with a spoon or with your fingers - no need for perfection here. Bake for 25 minutes. At this point it should be juicy and bubbly around the sides - if not, see notes. Sprinkle the top with turbinado sugar. Bake another 10 minutes and then finish with a few minutes under the broiler (475-ish) for a few minutes to get it golden brown and slightly crunchy on top. For the best saucy results, let it stand for 20-30 minutes before serving. But good luck with that. ??