-
1
Heat the oven to 350u00b0F (175u00b0C), with a rack in the center.
-
2
In a large microwave-safe bowl, combine the butter and sugar. Microwave in 30-second bursts, stirring between bursts, just until the butter is almost completely melted and the sugar has started to dissolve, about 2 minutes. (Alternatively, melt the butter and sugar in a saucepan over medium heat, being careful not to let the mixture come to a boil.)
-
3
Whisk the mixture until the butter is completely melted. Let cool for 5 minutes. Whisk continuously until the mixture is thickened and smooth and no longer looks separated, about 1 minute. Whisk in the vanilla and salt until combined. Add the flour and stir until no streaks of flour remain, then stir in half of the nuts.
-
4
Scrape the dough onto a rimmed 12 by 17-inch (30 by 43cm) baking sheet and pat it into a very thin, even layer with your hands. It won't look like you'll be able to fill the entire baking sheet, but you will! Just keep patting the dough to the edges. Use an offset or rubber spatula to smooth the top. Sprinkle the chocolate chips and the remaining nuts over the dough and press them down lightly with your hands.
-
5
Bake until light golden brown and slightly firm to the touch all over, 22 to 25 minutes, rotating the baking sheet every 7 to 8 minutes. Let the brittle cool completely in the pan on a rack.
-
6
Use a wide, thin spatula to loosen the edges of the brittle, then ease the whole slab of brittle onto the rack. Alternatively, if it looks like the slab might not come out cleanly, line a second baking sheet with parchment paper. Flip the brittle slab onto the paper and then immediately invert it right side up onto the rack, peeling off the parchment. Once completely cool, break into pieces-try to avoid smudging the chocolate chips. Store in an airtight container at room temperature.
