Zucchini fritter batter is very easy to make ahead. Zucchinis can be grated 1-2 days in advance and stored in the fridge. Any leftovers from corn on the cob (if used) will keep in the fridge for 3 days easily. The zucchini corn fritters batter mixed with all the ingredients will chill beautifully in the fridge for 2-3 days and will be ready for cooking. The chilled batter makes slightly crispier fritters!