Preheat to 350°F. Grease a 9-inch pie dish.
Combine graham crumbs, sugar, and melted butter. Press into pie dish and bake for 8–10 minutes until golden. Let cool.
Melt butter and chocolate chips in 20-second bursts. In a bowl, whisk both sugars, eggs, and vanilla until pale. Stir in melted chocolate.
Sift in flour, cocoa, baking powder, and salt. Gently fold to combine—don’t overmix.
Spread half the batter over the crust. Drizzle with caramel and sprinkle sea salt if using. Top with remaining batter.
Bake 25–30 minutes until edges are set and center is fudgy. A toothpick should have moist crumbs.
Cool 15–20 minutes. Slice and serve warm for a gooey texture or pair with vanilla ice cream.