Prep Peaches: Add the sliced peaches, sugar, lemon juice, and salt to a saucepan and stir to combine. *(If using canned peaches, skip steps 1 & 2 and follow the directions starting at step 3)

Cook on medium heat for just a few minutes, until the sugar is dissolved and helps to bring out juices from the peaches. Remove from heat and set aside.

Melt butter: Preheat oven to 350 degrees F. Slice butter into pieces and add to a 9x13 inch baking dish. Place the pan in the oven while it preheats, to allow the butter to melt. Once melted, remove the pan from the oven.

Make Batter: In a large bowl mix together the flour, sugar, baking powder, and salt. Stir in the milk, just until combined. Pour the mixture into the pan, over the melted butter and smooth it into an even layer.

Add fruit: Spoon the peaches and juice (or canned peaches, if using) over the batter. Arrange blackberries with peaches. Sprinkle cinnamon generously over the top.

Bake at 350 degrees for about 38-40 minutes. Serve warm, with a scoop of ice cream, if desired.