Please share a step-by-step recipe with ingredients and cooking instructions for a snack that's both tasty and nutritious. It should ideally be low in calories, sugar, and fat, and high in protein, fiber, and other healthy nutrients. Additionally, please ensure that the recipe is easy to follow, uses simple and easily accessible ingredients, and can be prepared within a reasonable amount of time. You may also include tips on how to customize the snack based on individual preferences, and suggest possible variations and substitutions.
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