Preheat the oven to 350 degrees
Bring 1/2 cup sugar, 1/4 cup brown sugar, juice from fruit, cornstarch, and lemon juice to a boil over high heat, stirring constantly. Stir in peach slices and simmer about 10 minutes, remove from heat and set aside.
In a large mixing bowl, cream together the melted butter and the remaining 1 cup of sugar
Add in the flour, baking powder, and salt until well sifted.
Add in the beaten egg and continue creaming together until it becomes a crumb mixture.
Spray the mason jars with cooking spray. Place jars in a large casserole pan to help keep them stable.
Fill up the jars approximately 3/4 of the way up, with the peach filling. Top the peaches evenly with the crumb mixture aprox 2 tablespoons of batter per jar.
Sprinkle with cinnamon or nutmeg, if desired.
Bake for 30-40 minutes or until the crumb top slightly brown.
