1 cup all-purpose flour
3/4 cup (1 1/2 sticks) unsalted butter, softened
1/3 cup brown sugar
1/2 cup sugar
3/4 cup semi-sweet chocolate chips
2 eggs, room temperature
1 tablespoon vanilla extract
1/2 teaspoon baking powder
1/4 teaspoon salt
Grease your slow cooker generously with butter or non-stick spray.
Cut out a piece of parchment paper the same size as the bottom of your slow cooker and set it inside the slow cooker insert. Grease paper with butter or non-stick spray as well.
In a medium bowl, whisk together flour, baking powder and salt until combined.
In a large bowl or mixer, cream together room temperature butter with sugar and brown sugar for 3-4 minutes, or until fluffy and lightened in color.
Beat in eggs, then add in vanilla extract, mixing until fully incorporated.
Gradually add flour mixture into wet ingredients, until dough comes together and sides of your mixing bowl are mostly clean, then fold in chocolate chips.
Note: depending on the size of your slow cooker and the desired height of your cookie, may need to double dough.
Transfer dough to greased and lined slow cooker and gently press into a flat layer with the edges of dough pressing against the sides of the slow cooker.
Place 2-3 layers of paper towel across the top of the slow cooker, making sure the edges extend out past the lid, then cover and cook on low for 3 hours. (The paper towels catch any moisture that would otherwise drop onto the cookies and prevent them from getting nice and crispy.)
To get a nicely crispy outer layer, turn heat to high for the last 30 minutes of cooking, leaving the lid only half on.
Once cooked, remove slow cooker insert and let cool at least 30 minutes, then run a knife around the edge of the cookie and invert onto a cutting board or serving platter.
Remove parchment paper, slice, serve and enjoy!