Thank him for the Snickers and put in the freezer or give it away (he never has to know). In future, let him know you've developed a passion for non-candy apology gifts. Like diamonds! Ok, fine, maybe fruit?
As for your work functions, are they things where you're asked to bring something? If so, try
www.cookinglight.com for some really amazing recipes YOU can bring to share and enjoy. They have a healthy alternative for anything you can think of.