Preheat the oven to 350°F (180°C). Spray an 8 x 8–inch pan with nonstick cooking spray and line the pan with parchment paper with an overhang on two sides. Spray the parchment paper with nonstick cooking spray and set it aside.
To Make the Espresso Caramel:
In a medium saucepan over medium heat, add the granulated sugar, stirring with a high heat–resistant rubber spatula or wooden spoon. The sugar will form clumps and eventually melt into a thick, amber-colored liquid as you continue to stir. Be careful not to burn it!
Once the sugar is completely dissolved, about 10 minutes, immediately add the butter and stir until melted, about 2 minutes. (Be careful with this step, because the caramel will bubble rapidly when the butter is added.)
Very slowly drizzle in the heavy cream while stirring. Allow the mixture to boil for 30 to 45 seconds, then remove it from the heat. Stir in the espresso powder and salt and set it aside until needed.
To Make the Carmelitas:
In a large bowl, combine the melted butter, light brown sugar, vanilla, flour, oats, baking soda, and salt. Stir everything together with a fork. Press half of the mixture into the prepared pan. Bake for 10 minutes.
Remove the pan from the oven and sprinkle the top evenly with the chocolate chips and pecans, and then with the espresso caramel. Crumble the remaining oat mixture over the caramel. Return the pan to the oven and continue to bake for 18 to 20 minutes, just until the edges are lightly browned.
Remove from the oven. Cool in the pan on a wire rack at least 3 hours before removing and cutting into bars.
Cover and store leftover bars in an airtight container at room temperature for 2 to 3 days.