Slowly mix in flour until the mixture is just combined. Press about 2/3 of this mixture in the bottom and about 1/2” up the sides of the prepared pan. Spread dulce de leche over the top, then sprinkle the remaining dough over the bars. Bake for 22-25 minutes, or until the top looks done and is golden around the edges.
These Dulce de Leche Magic Bars are similar to classic Magic Bars but with dulce de leche instead of condensed milk. Dulce de leche is one of my favorite flavors. It’s a bit like caramel but with a little different taste and texture. With these bars, that wonderful flavor combines with chocolate, nuts, and more for an amped up version of a classic.
Spread the dulce de leche evenly on top of the shortbread layer, then refrigerate for 30 minutes. For the chocolate layer: In a heatproof bowl, combine the dark chocolate chips and butter, and microwave in 30 second intervals until it's almost smooth.
Heat dulce de leche in microwave on medium power until it is soft enough to spread. 2-4 minutes total- I microwave for 45 seconds, stir, then zap again on med power. Spread dulce de leche over baked crust. Sprinkle toffee bits and the 1 cup of oats mixture over that.