Dairy-free/vegan zucchini cake: substitute two flax eggs (mix 1 Tbsp ground flaxseed with 3 Tbsp hot water. Let sit for 1 minute until it gets gloopy), substitute ⅓ cup vegan mayo for the sour cream.
Make Ahead Instructions: The cake can be baked and frosted, stored in the refrigerator, 1-2 days in advance.
Freezing Instructions: Freeze frosted or unfrosted zucchini cake for up to 2 months. Cover well with plastic wrap and aluminum foil before freezing. Thaw in the refrigerator overnight.