Place nuts on a large sheet pan lined with parchment. Roast in 325°F oven for 10 minutes.
Place olive oil, vegan butter, honey and rosemary in a small microwave safe bowl, heat for 30 seconds. Stir.
Remove walnuts from oven, stir into honey mixture and spread back onto baking sheet. Sprinkle with salt. Roast another 7-10 minutes.