S'mores Bars

Saw this on TikTok and wanted to make it. Not all of the amounts were given, so I'm playing to figure it out, but they are sooo good! 

1/2 c melted butter

1/2 c brown sugar

1/3 c white sugar

1 egg

1 t vanilla

1/2 T baking soda

1/2 t (or so) kosher salt

1 1/4 c flour

2/3 c (or so) chocolate chips

16 marshmallows

Chocolate bar (I used Symphony with toffee and almonds because that's what I had on hand - yum!)

5 Graham Crackers

Preheat oven to 350.

Line a 9x9 baking dish with parchment paper.

Line the bottom of the dish with graham crackers. 

Cream butter and sugars. Add egg and vanilla. Mix until lightened. Add dry ingredients, just until mixed. Add chocolate chips.

Spread 1/2 of the cookie mixture on the graham crackers.

Layer with marshmallows and chocolate bar.

Spread the remaining cookie mixture on top - aiming mostly for the marshmallows.

Optional - sprinkle with flaked salt.

Bake for 35-40 minutes.

(After 25 minutes, cover with foil.)