Preheat oven to 350 degrees. Spread sugar cookie mix on a 9x13 or larger baking sheet. Cook for 5 minutes. Remove from oven and let cool before using in truffles.

Line a small baking sheet with parchment paper, set aside.

Use electric mixer to beat together cooled sugar cookie mix, butter, vanilla extract, and 7 ounces of the sweetened condensed milk. Mix until a large ball is formed. If mixture is too crumbly to form into a ball, slowly add more sweetened condensed milk, about 1 teaspoon at a time, until a large, soft ball forms.

Form mixture into balls about 1/2 to 3/4 tablespoon in size. Place on parchment lined baking sheet. Place balls into freezer for at least one hour.

In a microwave safe bowl, stir together white chocolate chips and vegetable oil. Cook on 50% power, stirring every 30 seconds, until chocolate is completely melted and smooth.

Remove balls from freezer. Use a fork to dip balls into melted chocolate. Shake off excess chocolate and place dipped ball on parchment paper. White chocolate is still wet, decorate with sprinkles as desired.

Let candy sit for at least one hour, or until chocolate is firm.