Make the caramel filling first so that it can thicken up before we use it to top the brownies.

Heat ⅔ cup of sweetened condensed milk, ¼ cup butter, ¼ cup packed brown sugar, and 2 tablespoon light corn syrup over medium heat in a heavy saucepan. Stir frequently and let the mixture just begin to bubble.

Once this happens, turn the heat down to low to let the caramel simmer.

Continue to stir frequently until the mixture thickens and becomes a medium caramel color (about 5-7 minutes).

Remove from the heat and stir in 1 teaspoon vanilla extract and ½ teaspoon fine salt.

Pour into a separate container, then set aside to cool to room temperature.

Preheat the oven to 350°F/175°C. Line an 8×8-inch square baking pan with parchment paper.

Use a fork or pastry cutter to combine ½ cup butter, 1 cup flour, ¼ cup powdered sugar, and ¼ teaspoon fine salt.

Press into the bottom of the prepared pan with your fingers. Prick the crust thoroughly with a fork, then bake for 22-25 minutes, or until the edges are just starting to brown.

Place the pan on a wire rack to cool. Keep the oven on, but lower the temperature to 325°F/163°C.

In a medium bowl, mix together 1 ½ cups of sugar, ¾ cup of flour, ⅔ cup of cocoa powder, ½ cup of powdered sugar, ½ cup of chocolate chips, and ½ teaspoon of salt.

In a large bowl, whisk together 2 large eggs, ¼ cup vegetable oil, ¼ cup melted butter, 2 tablespoon water, and 1 teaspoon vanilla.

Pour the dry mix into the wet ingredients and stir until just combined.

Pour the batter over the shortbread crust in the prepared pan and smooth it into an even layer. Bake at 325°F/163°C for 38-43 minutes.

Set on a wire rack to cool fully before topping.

Heat ½ cup of heavy cream in a heatproof bowl in the microwave for 45 seconds.

Gently pour ⅔ cup of dark chocolate chips into the heavy cream. Let the mixture sit for 1 minute.

Stir slowly until the cream and chocolate combine and the mixture is smooth.

Mix in 2 tablespoon of room temperature unsalted butter, 1 tablespoon corn syrup, and ¼ teaspoon fine salt until combined.

Cover with plastic wrap to prevent the ganache from forming a skin, then set aside to cool to room temperature.

Once the brownies are fully cooled, scoop the room-temperature caramel on top and spread it into an even layer.

Then spread the room-temperature chocolate ganache on top of the caramel.

Add a sprinkle of flakey sea salt, then use a sharp, warm knife to cut into the chilled brownies.

Leftover brownies can be kept at room temperature in an airtight container for 2 days or in the fridge for up to a week.