Use Granny Smith apples and Red Onions . The tartness of the green apple stands up to the high heat, and the red onion adds a pop of color and a mild, peppery finish.
When cooked together, apples and onions undergo a beautiful transformation. The natural sugars in the apple caramelize alongside the pungent compounds of the onion, resulting in a complex, mellow profile that enhances everything from roasted meats to simple side dishes. The Science of the Pairing Apple Onion
Use Gala or Fuji apples with Yellow Onions . These apples break down easily into a sauce-like consistency, while yellow onions provide a deep, classic savory base. Use Granny Smith apples and Red Onions