Preheat your oven to 350°F (175°C). This ensures that your cookie bars will bake evenly and come out perfectly golden.
Line a 9x13 inch baking pan with parchment paper, leaving some overhang on the sides. This will make it easy to lift the bars out after baking.
In a large mixing bowl, beat the unsalted butter, light brown sugar, and granulated sugar together until light and fluffy, about 2-3 minutes.
Add in the eggs, vanilla, and instant coffee. Continue to mix until well combined.
In a separate bowl, whisk together the all-purpose flour, baking soda, and kosher salt. Gradually add this to the wet ingredients, mixing until just combined.
Gently fold in the semi-sweet chocolate chips until evenly distributed.
Spread the cookie dough mixture evenly into the prepared baking pan and smooth the top with a spatula.
Bake for about 15-20 minutes, or until the edges are golden and a toothpick inserted in the center comes out clean. Allow to cool slightly.
In a medium saucepan over medium heat, combine the granulated sugar and heavy cream. Stir continuously until dissolved and bubbling, then simmer for about 5-7 minutes until light amber.
Remove from heat, stir in the unsalted butter and sea salt, and add Kahlua if using. Stir until smooth.
Pour the caramel over the slightly cooled cookie layer and spread it out evenly.
Sprinkle Rice Krispies over the caramel layer, pressing gently to adhere.
Allow to cool completely at room temperature. Lift out using parchment paper and slice into squares.
