In an 8x8" glass pan, toss together the onion, garlic, oil, and salt. Bake for 30-35 minutes, stirring every 10 minutes, until they're nice and browned. This is longer than you'd normally roast onions, that that's no accident. During the last 15 minutes of cooking, check in every 5 minutes and stir. You want lots of sweet, crispy browned onions to come out of this pan!
Making the Dip
Reserve ½ cup of the roasted onions.
Add the remaining roasted onions, the clove of roasted garlic, any oil remaining in the pan, and the Dip Ingredients to your blender. Puree until smooth, adding more water by the tablespoon, as needed, to get things moving.
Transfer to a small bowl, and stir in the reserved roasted onions.
Chill until you're ready to serve. Make sure you serve with plenty of chips for dipping!