Store leftover keto cottage cheese flagels in an airtight container in the refrigerator for up to five days, or freeze individually wrapped for up to one month. Reheat in a toaster oven or dry skillet to restore the crisp crust and chewy center, avoiding long microwave times that can soften the texture. Customize the flavor by using different toppings such as poppy seeds, coarse salt, or grated Parmesan, and serve them as sandwich bases, mini pizza crusts, or simply with butter and avocado for a quick keto breakfast.