Preheat oven to 350°F. Grease an 8x8 pan.

In medium saucepan melt together butter and chocolate until smooth.

Remove from heat and whisk in cocoa, sugar, and salt. The batter will be really thick and granular.

Blend in the vanilla then quickly beat in the egg. Whisk in the flour.

Scrape the batter into the pan and smooth with a spatula. Press the wafers on top of the brownie batter.

In a large bowl, beat together the cream cheese and sugar until smooth. Add the eggs one ay a time, beating after each addition.

Add the lemon juice and vanilla. Pour the batter on top of the kit kat layer.

Bake 35-40 min or until the top is firm but still wiggles a bit. (toothpick should come out clean)

Let cool to room temperature then refrigerate for at least 4 hours.