Preheat the oven to 190C.
Next, prepare the courgette and sweet potato. To do this I actually have a food processor with grating blades. This makes the process SO easy and takes just a couple of minutes.
Simply peel the skin from the sweet potato, chop in half and feed into the food processor to be grated. Alternatively, you can grate the veggies by hand. If nothing else, you'll get in a little bit of a workout. But it only takes a few minutes, and voila. *
Once the vegetables are grated, you can prepare the egg mix. Begin by combining the eggs, milk, and seasonings and mix thoroughly.
You can either add the cheese directly into the mix at this point. Or, I like to sprinkle it on top, before baking, for a crispy, cheesy top.
Add the sweet potato and courgette to the egg mixture then add the baby spinach. I like to roughly tear it, just to make it combine into the mixture more easily.
Line an 8" square pan with parchment paper and pour the egg mixture into the pan.
Sprinkle the cheese on top and, optionally, some sliced tomato then bake in the oven for around 50 minutes.
Once baked, you can either eat immediately or leave to cool completely and then transfer to an airtight container and store in the fridge for up to 5 days.These egg squares can then be eaten as a healthy snack, one square at a time. I also like to combine two squares to serve along with a salad bowl and grains, for a more padded-out meal.