Preheat the oven to 350 degrees.
In a medium bowl, whisk together the flour, baking powder and salt. Set aside.
On medium low speed, beat the butter and sugar for about three minutes, until it is light and fluffy. Then add the vanilla, and one egg at a time, combining for about thirty seconds after each addition.
Gradually add the flour mixture until it is well combined, scraping down the sides of the mixing bowl as necessary.
Press the cookie dough into the bottom of a 9x13 inch pan and bake for about 20 minutes. Let it cool on the counter for about 10 minutes, and then put it in the refrigerator for a half hour.
While the Sugar Cookie layer cools, make the next layer. Soften the butter in the microwave for about thirty seconds. Add the cookie butter and put it back in the microwave for another 30 seconds at half power. Whisk in the powdered sugar until it is smooth. Put it over the cooled (it does not have to be completely cooled) sugar cookie layer, and spread it until it is even. Put it back in the refrigerator for another 30 minutes.
While the Cookie Butter layer cools, melt the butter and chocolate together, either over low heat on the stove top, or in the microwave on half power. Once the Cookie Butter layer is set, spread the chocolate layer over it and let it set for another 30 minutes to an hour.
When yo go to cut the bars, make sure they come to room temperature, or the chocolate will crack and break.