Chocolate filling:
2 cups semisweet chocolate chips
1 can sweetened condensed milk (14 oz)
2 tsp vanilla extract

Cookie dough:
1 cup unsalted butter at room temperature (2 sticks)
1 cup light brown sugar
1/2 cup granulated sugar
1 large egg
1 large egg yolk
1 Tbsp vanilla extract
2 cups all-purpose flour
1 cup quick-cooking or old-fashioned rolled oats
1 teaspoon baking powder
1 teaspoon baking soda
1 teaspoon kosher salt
Optional -- 2 cup chocolate chips or chopped nuts

Preheat oven to 350 degrees F. Lightly butter a 9x13-inch pan with parchment paper, allowing enough overhang on the long side to lift the bars from the pan.
Prepare the gooey chocolate filling: Place the chocolate chips and condensed milk in a small saucepan over the lowest possible heat and cook, stirring constantly, until the chocolate has melted and the mixture has thickened, 3 to 5 minutes. Turn off the heat, add vanilla, and stir until smooth. Set aside to cool to room temperature.
Prepare the cookie dough: Place the butter and sugars in a large bowl (or stand mixer). Beat with an electric mixer until smooth and creamy. Add the egg, egg yolk and vanilla. Beat well. Whisk together the flour, oats, baking powder, baking soda and salt in a medium bowl. Add to the butter mixture. Beat until everything is well incorporated, scraping down the sides of the bowl as needed. Stir in the chocolate chips.

Prepare the bars: Using half of the batch of cookie dough, place dollops into the prepared pan and press down lightly to even it out. Pour the cooled chocolate mixture over the dough and then add small dollops of the remaining dough on top. Don't worry if the dollops don't completely cover the chocolate mixture. Just spread it together as much as you can, and let some chocolate peek through.

Bake until lightly browned, 20 to 25 minutes. Set aside to cool completely, then cut into bars. Makes about two dozen bars.

Tips: I halve the amount of gooey chocolate filling. (Actually, I make a full batch, put half on the cookies, and put the rest on pancakes in the morning.) You can substitute peanut butter or butterscotch chips in the filling, but it makes it very sweet.

Kris
Recipe from recipegirl.com

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