Preheat the oven to 350 F. Line a 12 cup muffin pan with paper liners. In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with sugar until fluffy.
Add in egg and vanilla extract until smooth. Add in the flour mixture, mix until it is fully combined. Fold in the cocoa pebbles cereal and chocolate chips. Evenly divide the cookie dough between the prepared muffin pan. Bake for 12-15 minutes.