You do not want to freeze this keto eggplant pizza. When you freeze the eggplant, it will get mushy and will not hold up well. All of it together just makes for an unappealing meal. You can make the keto pizza ahead of time by making the eggplant and baking it until it is ready. If you cook just the eggplant ahead of time, just let it cool and store in the refrigerator for up to 2 days until you are ready to top and serve. Top as you normally would and cook for 8 to 10 minutes until the toppings are heated through and the cheese has melted. You can also cook completely and store it in the refrigerator for up to 2 days before serving. Just pop them into the oven on higher heat for a few minutes to heat through before serving. I do not recommend reheating in the microwave as the result will be a soggy base.