In a medium bowl mix oats, 1/2 cup peanut butter, honey and vanilla extract. Stir together until fully combined.
Add 1 ½ cups of the oat mixture into the bottom of the prepared dish. Press the mixture down firmly in an even layer. Make sure it's pressed down firmly and is very compacted to set the layer.
Next, make the chocolate layer. Add 1/3 cup peanut butter and chocolate chips to a microwave-safe bowl and then microwave in 20-30 second intervals, stirring in between until the chocolate chips have melted. Stir the mixture until chocolate and peanut butter is fully mixed.
Pour chocolate mixture evenly over oat mixture.
Crumble remaining oat mixture evenly over the top (the chocolate will peek through). Drizzle with extra melted peanut butter and sprinkle with mini chocolate chips.
Refrigerate for at least 2-3 hours before cutting into 12 even bars. Refrigerate or freeze remaining bars. Note: You can also slice into 16 small squares or 9 squares for a bigger bar.
Notes
Make sure to line your pan with parchment paper or the bars will be very difficult to remove and will turn out crumbly.Don't skip the fridge time! These bars need the full 2 hours to reach their best texture.