01 -
Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking pan well, or line it with parchment and grease the parchment.
02 -
Prepare the cake mix with the eggs, oil, and water listed on the box. Beat until the batter is smooth, about 2 minutes.
03 -
Spread half of the batter in the prepared pan. Bake for 15 minutes, until the surface looks set but the cake is not fully baked.
04 -
While the cake starts baking, combine the caramels, evaporated milk, and butter in a saucepan over low heat. Stir often until smooth and pourable, 6-8 minutes.
05 -
Pour the caramel over the warm cake base. Sprinkle with 1 cup pecans and the chocolate chips, keeping the layer even.
06 -
Spoon the remaining cake batter over the filling in small dollops. Gently spread it to cover most of the caramel, then sprinkle with the remaining 1/2 cup pecans.
07 -
Bake for 22-26 minutes, until the top springs back lightly and the center no longer jiggles. A few caramel bubbles at the edges are normal.
08 -
Cool completely in the pan for at least 2 hours. Sprinkle with flaky salt if using, then cut into squares with a clean knife.