Preheat oven to 350°F. Line a 9×9-inch pan with aluminum foil and spray with cooking spray. Lining your pan is highly recommended for ease of cleanup due to the stickiness of the caramel; set pan aside.
In a large mixing bowl, mix together the softened butter and dark brown sugar until smooth.
3/4 cup butter, softened, 1 cup dark brown sugar
Add egg + yolk, vanilla, and whisk until smooth.
1 whole egg + yolk, 2 teaspoons vanilla extract
Add the flour, oats, baking soda, and sea salt. Stir until combined. Stir in 1/2 cup chocolate chips.
1 1/2 cups all-purpose flour, 1 1/2 cups rolled old-fashioned oats, 1 teaspoon baking soda, 1/2 teaspoon sea salt, 1 cup semi-sweet chocolate chips or chunks, divided
Add 2/3 of the mixture to the prepared pan (just eyeball it), and smooth it with a spatula or the back of a spoon to create an even, smooth, flat layer; set the remainder aside.
Bake for 10 minutes. While it bakes, make the caramel sauce.
In a large microwave-safe mixing bowl, combine the caramels, cream, butter, and sea salt. Heat on high power in 60-second bursts to melt the caramels, stirring after each burst.
35 wrapped caramel squares, 1/2 cup heavy cream, 1 Tablespoon unsalted butter
After 10 minutes, remove the pan from the oven and evenly sprinkle with the remaining chocolate.
Slowly and evenly pour the caramel sauce over the chocolate.
Evenly crumble the reserved oatmeal-brown sugar mixture over the top. Return the pan to the oven and bake for about 15 to 18 minutes or until the edges are lightly browned and the center is bubbling slightly.