With racks in upper and lower thirds of oven, heat oven to 325°. Line two baking sheets with parchment. In food processor, combine almonds, pecans and walnuts; pulse to roughly chop. Add to a large bowl with Grape-Nuts and Rice Krispies.Advertisement
In a small bowl, whisk egg whites, maple syrup and salt; pour over nut mixture and mix well. Spoon loose tablespoonfuls onto prepared baking sheets. Bake 23 to 25 min, rotating pans halfway through. Cool on pans 5 min, then cool completely on rack. Store in an airtight container for up to 1 week. Makes about 40 clusters. Swap It: Sub in 3 cups of any nuts. And try honey instead of syrup.