Pre-heat oven to 180°C / 350°C (160°C fan-forced). .
Grease and line a lamington tray (16 cm x 26 cm). You can also use a half sheet baking tray, a slice pan, or a deep cookie tray.
Mix the flour and baking powder together. Set aside.
Wash and peel the carrot. Shred using a hand shredder or the shredder attachment of a food processor.
Wash and cut off the ends of the zucchini. Shred using a hand shredder or the shredder attachment of a food processor.
Place the eggs in a large bowl and whisk together.
Add the shredded zucchini, shredded carrot, onion, cheddar cheese, salt, herbs, red chili flakes, and chopped onion flakes.
Stir together till all the ingredients are mixed, and a batter is formed.
Pour the batter in the greased and lined tray. Bake in the pre-heated oven for about 35 – 45 minutes till the mixture is set, and the top is light golden brown. The total baking time will vary depending on the baking tray used. If your oven has a grill, you can turn it on for the last few minutes of baking for a crispier top.
Remove the slice from the oven, and let it cool for a few minutes. It will firm up and be easier to cut after it has cooled down a little.
The zucchini slice can be kept for up to 4 days in the fridge in an airtight container in the fridge. The zucchini slice will feed 4 - 6 people if eaten as a main course for lunch or dinner, and 8 people if served as a snack or appetizer.
Freezer Instructions: Wrap the slice pieces individually in plastic wrap, then place in an airtight container or in sealed freezer bags. Keep in the freezer for upto 3 months. To defrost, let the slices thaw at room temperature, or place in the fridge to thaw overnight. If you are adding to kids lunch boxes, frozen zucchini slices can be added to lunchboxes in the morning, and they will thaw by lunch time.