Preheat the oven to 350°F (175°C). Line a 9 x 13-inch pan with nonstick foil or parchment and lightly grease it.
Pulse the flour and sugar in a food processor to combine.
Add the cold butter cubes to the flour mixture and pulse until the butter pieces are about the size of small peas.
Add the two egg yolks and pulse just until the dough begins to come together.
Press the dough evenly into the prepared pan and bake until the edges are lightly browned, about 12–14 minutes. Remove and let cool while you make the caramel.
In a medium saucepan, whisk together the caramel ingredients (as specified in your recipe source). Cook over medium heat, stirring often, until it reaches a boil.
Clip a candy thermometer to the pan and continue cooking and whisking until the caramel reaches 225°F (about firm ball stage). Remove from heat.
Pour the hot caramel evenly over the cooled crust and let it cool until the caramel is set.
To make the ganache, combine chopped chocolate, heavy cream, and corn syrup in a microwave-safe bowl. Heat gently in short bursts, stirring between intervals, until the chocolate is almost melted.
Let the mixture rest for a couple of minutes, then stir until completely smooth. Spread the ganache over the caramel layer.
Chill the bars for at least 1 hour to set the ganache before cutting into squares.