Delicious chocolate crisps, topped with toffee bits and flaky salt. Great for snacking or gifting! Having a Silpat or other silicon baking mat is helpful for this recipe.
Preheat oven to 325F with oven rack in centre of oven. Prepare a heavy baking sheet with a Silpat or similar silicone baking mat. (*You can use parchment paper, it's just a little trickier to spread the batter, as the paper will move around on you. Tricky, but do-able if that's all you have on hand, so give it a go :)
In a medium bowl, whisk the egg whites until really foamy. Add the sugar and whisk until smooth and creamy. Whisk in the vanilla. Add the melted/cooled butter and whisk to combine. Add the cocoa powder and flour and use a rubber spatulala to fold in just until blended.
Pour batter on to prepared baking sheet. Using a spatula, spread the batter evenly in to a 9 1/2-inch x 14 1/2-inch rectangle (if using a Silpat, that would be the exact size of the inner cream coloured area, excluding the orange border area). Try to get the batter as evenly thick as possible. Scatter top with milk chocolate chips.
Place in pre-heated oven and bake for 20 minutes. Remove from oven and using a pizza cutter, cut in to squares about 1 1/2-inches square, but do not break apart the squares. Return to the oven and bake a further 6-8 minutes or so, or until crisps look flat and firm. Remove from oven. Sprinkle with toffee bits and flaky salt. Allow to cool on the baking sheet for 3-4 minutes, then carefully slide the crisps still on the silpat on to a cooling rack to cool completely. Break apart once fully cooled. Store in an airtight container.
Notes
Be sure to read the "Cook's Notes" in the original post, for more tips, options, substitutions and variations for this recipe!