Roasted Onion and Cheddar Dip

I love to make dip but I haven't tried this one yet, so I'm posting it here for safe-keeping. Found this in the Early Summer edition of Food & Drink magazine from the LCBO.

• Ready In: 30 mins
• Serves: 8
• Yields: 1 1/4 cups

Ingredients

• 1  small onion, finely chopped
• 2  tablespoons cider vinegar or 2  tablespoons beer
• 1  teaspoon butter
• 1⁄4 teaspoon fresh ground black pepper
• 4  ounces cream cheese, softened
• 1  cup  shredded aged cheddar cheese (aged 2 years (or more)
• 1⁄2 teaspoon dry mustard or 1⁄2 teaspoon Dijon mustard
• 1  teaspoon  chopped fresh thyme or 1⁄4 teaspoon dried thyme
•  thick  pretzel, for dipping

Directions

1. Preheat the oven to 450°F or barbecue to medium-high.
2. Combine onion, vinegar, butter, and pepper in a shallow baking pan (for oven) or in a foil pan (for barbecue). Roast, stirring twice, for 15 to 20 minutes or until soft, translucent and starting to brown. Let cool slightly.
3. Mash softened cream cheese in a bowl. Add onion mixture, cheddar, mustard and thyme, stirring until well blended. Pack into an oven-proof ramekin or serving dish or a foil pan. Cover and refrigerate until serving, for up to 2 days.
4. To serve, preheat the oven to 350°F or barbecue to medium-high.
5. Heat dip, uncovered, in oven or on grill, for about 15 minutes or until hot and bubbling around edges. Stir and serve with thick pretzels for the dipping (the thicker the pretzels, the better chance that they won't snap and they'll hold more dip).