Preheat oven to 350 F. Line a 12 cup muffin pan with cupcake liners. In a medium bowl, whisk together flour, salt and baking soda.
In a large bowl with a mixer, beat softened butter with granulated sugar until fluffy. Add in egg and vanilla extract, beat until smooth. Add the flour mixture in three additions, beating after each until all of the flour is incorporated.
Roll dough into balls and place each one into a prepared muffin tin. Bake for 15 minutes. Remove from oven and place one chocolate on top of each cookie cup. Let cool completely.
