Step 1
Preheat the oven to 375 degrees F (190 degrees C). Lightly butter a 9-inch cast iron skillet and set aside. Reserve remaining butter.
Step 2
Combine flour 2 tablespoons sugar baking powder salt and cinnamon in a bowl. Cut in 1/2 cup cold butter with a pastry knife until the mixture resembles coarse meal. Pour in milk and stir just until the dough starts to come together.
Step 3
Turn dough out onto a lightly floured surface and shape into a ball. Divide ball in half and lightly knead each half. Gently roll each half into a 9-inch circle.
Step 4
Place 1 dough circle into the prepared skillet and dot with reserved butter. Place second dough circle on top of the butter pieces and place the skillet in the center of the preheated oven.
Step 5
Bake in the preheated oven until top is lightly browned 22 to 25 minutes.
Step 6
While the shortcake is baking prepare peaches. Slice 1 peach toss with 1 teaspoon lemon juice and set aside. Chop the remaining peaches yielding about 4 cups and toss with remaining lemon juice.
Step 7
Turn shortcake out onto a rack to slightly cool about 5 minutes. Slice in half crosswise using the edge of the second layer as a guide. Place bottom half on a serving plate cut side up.
Step 8
Sprinkle 1/4 cup white sugar on a plate and lightly mash 2 cups of peaches into the sugar. Spread out mashed peaches and sugar over the shortcake layer on the serving plate. Cover mashed peaches with the second shortcake layer cut side up.
Step 9
Toss remaining chopped peaches with remaining sugar and distribute on top of the second layer. Toss peach slices in any remaining juice and place in a decorative pattern on top of the shortcake.