Preheat oven to 350 F. In a medium bowl, whisk together flour, salt and baking soda. In a large bowl, using a mixer beat softened butter with both granulated and brown sugar until fluffy.
Add in eggs and vanilla extract, beating until smooth. Add flour in three seprearte additions, beating after each until all of the flour is icorporated. Fold in sprinkles.
Spread cookie dough out into a large baking dish. Bake for 25-30 minutes. Let cool completely.