Heat the oil in a large skillet over medium-high heat. Add the onion, season with 1/2 tsp. salt, and sauté, stirring often, until the onion softens completely and starts to brown, about 9 minutes. Transfer to a food processor and add the cream cheese, sour cream, thyme, and cayenne. Pulse until the mixture is well combined. Season with salt and pepper to taste. Refrigerate until ready to serve.
Serve with pita chips.
Photo: Scott Phillips