Wash brussels sprouts and peel away any discolored leaves. Cut sprouts in half lengthwise. Steam over boiling water for about 5 minutes. Drain.

In a large skillet, heat butter and olive oil over medium-high heat. Add sage and nuts and stir with a wooden spoon or spatula until pecans start to brown and sage wilts. Add brussels sprouts, season with salt and pepper, and toss. Cook for about 5 minutes, browning sprouts slightly on the bottom and stirring to prevent burning. Reduce heat and cook another 3 minutes or so. Serve warm.