Preheat: Set your oven to 350°F and position a rack in the center.
Pre-bake the bottom crust: Roll out one pie crust and press it into the bottom of your baking dish (no need to grease). Sprinkle with a little cinnamon and sugar, then rub it gently into the dough. Bake for 10 minutes — it will look just set, not brown. Set aside.
Start the filling: While the crust bakes, melt the butter in a large saucepan over medium heat. Add the frozen peaches straight from the bag and let them simmer for 5 minutes, stirring occasionally — they'll release a lot of liquid. Listen to the sizzle and inhale the sweet steam; your kitchen will smell like a southern orchard.
Add the sweets and spices: Stir in lemon juice, vanilla, granulated sugar, brown sugar, cinnamon, and nutmeg. Continue simmering over medium heat for 10 minutes, stirring every couple of minutes. The mixture should thicken noticeably and look like a jammy syrup when you lift the spoon. You'll see the bubbles slow down and the liquid turn into a glossy, deep amber sauce. This step is where the magic happens — don't rush it or you'll end up with watery filling.
Assemble: Pour the hot peach filling over the pre-baked crust. It should spread evenly, releasing one last puff of fragrant steam.
Top with crust strips: Roll out the second crust and cut it into 1-inch wide strips. Arrange them in a lattice or just lay them crosswise over the peaches. Don't worry about perfection — rustic is the whole point.
Final sprinkle: Sprinkle a little more cinnamon and sugar over the top crust.
Bake: Place the dish on a baking sheet to catch any drips, then bake for 50 minutes. The southern peach cobbler is done when the crust is deep golden brown and the filling bubbles up through the gaps. If the top is browning too fast at 40 minutes, tent loosely with foil for the last 10.
Rest: Let it sit on the counter for at least 15 minutes before serving. This lets the filling set up so it doesn't run all over the plate. The crust will crackle as it cools, revealing the jammy fruit beneath. That sound? Pure comfort.