01 -
Line an 20x20 cm baking pan with parchment paper or aluminum foil and set aside.
02 -
In a large bowl, beat the softened butter and light brown sugar until fluffy, about 3 minutes. Add vanilla extract and mix until combined.
03 -
On low speed, alternate adding all-purpose flour and sweetened condensed milk to the butter mixture until just combined. Gently fold in mini chocolate chips.
04 -
Press the sticky dough evenly into the prepared pan. Lightly flour your hands if needed to prevent sticking.
05 -
Cover the pan with plastic wrap and refrigerate for 3 hours or overnight until firm.
06 -
Combine peanut butter and milk chocolate chips in a microwave-safe bowl. Heat in 30-second intervals, stirring until smooth.
07 -
Pour and spread the peanut butter mixture over the chilled dough layer. Refrigerate for at least 1 hour until set.