Line a cookie sheet with a silphat mat or parchment paper.
In a bowl whisk the egg whites until foamy
Add in sugar and then cocoa powder, oil and vanilla until smooth.
Add in salt and baking powder.
Add the flour and stir until smooth.
Pour batter onto lined cookie sheet and spread as thinly as possible with back of spoon.
Sprinkle with chocolate chips and then sprinkle with toffee bits.
Bake in a 325 oven for 20 minutes.
Remove from oven and use a pizza cutter to cut into "shrad" shaped pieces.
Return to oven for 5 more minutes.
Remove form oven and cool. Break into pieces.
If any of the pieces are too thick and chewy you can return them to the oven at 250 degrees for 20 more minutes and then re-cool.
Video
Notes
Spread it thin and evenly. The thinner you spread the brownie batter, the crispier your brittle will be. Try to keep the thickness as even as possible so it bakes at the same rate.
Use parchment paper. Lining your baking sheet makes the brownie brittle easy to remove after baking and makes cleanup easier too.
Watch it closely. Because the batter is spread so thin, it can go from perfectly crisp to overbaked quickly. Keep a close eye on it toward the end of the baking time.
Cut while still warm. If you want to have even edges, cut your brittle while still warm. It will continue to crisp up as it cools. Or if you prefer, let it cool completely and just break into pieces.
Keep it crispy. Store Brownie Brittle in an airtight container at room temperature to help maintain that delicious crunch.
If any of the pieces are too thick and chewy you can return them to the oven at 250 degrees for 20 more minutes and then re-cool.