Remove the pan from the heat and let cool to 220°F, about 5 minutes. Add the butter and stir just until melted and the mixture is creamy, about 1 minute. Stir in the walnuts, pecans, and nutmeg. Immediately, using a tablespoon, scoop up spoonfuls of the mixture and drop onto the prepared baking sheets, spacing them evenly. If the mixture becomes too dry to drop, add 2 tablespoons cream and stir over low heat until melted.