In an extra large mixing bowl, beat butter with an electric mixer for about 30 seconds. Add brown sugar, granulated sugar, baking soda, and salt. Beat until well combined, scraping down the sides of bowl occasionally.
Beat in eggs, oil, and vanilla. Beat in the flour a little at a time.
Add in the cereal and 2 1/2 cups of the crushed malted milk balls, reserving a 1/2 cup to sprinkle on top of cooked cookies.
Using a tablespoon sized cookie scoop, shape dough into 1-1/2-inch balls.
Place balls 2 inches apart on an ungreased cookie sheet.
Bake for 8 to 10 minutes or until golden.
Remove from oven and immediately sprinkle the reserved malt ball crumbs over the tops; let sit for about 1-2 minutes and transfer to a wire rack to cool completely.