Make the compound butter: Combine butter and saffron powder in a small bowl and mix until fully incorporated. Salt to taste. Place butter on a piece of plastic wrap and roll into a small log. Chill for at least 2 hours. It will keep for 2 weeks, refrigerated.
Make the salad: Roughly chop the chard leaves. Set a large pan over medium heat, add the olive oil, and heat 2 minutes. Add the chard and cook, stirring occasionally. Add 1⁄4 cup water, cover with a lid, and cook until tender, about 10 minutes.
Season with salt and pepper. Serve warm with a slice of the saffron butter on top.