545gsweet potato (4 ½ cups)peeled then cut into evenly sized chunks.
1largered onion (190g)peeled, cut in half then sliced thinly.
150gfeta cheese (1 cup)crumbled roughly.
100gpurple sprouting broccoli (1 handfull)woody ends removed then any large stems cut in half lengthways.
1 tbspolive oil
1clove of garlicminced.
1heaped tbsp fresh thyme leaves
¾tspsea salt (divided into ½ a tsp and ¼ tsp )
½tspcracked black pepper
Preheat the oven to 180C/356FBring a large saucepan of water to the boil, add the sweet potatoes then cook for 10 minutes. Or until the sweet potato is tender. Drain and set aside.
While the sweet potato is cooking, heat 1 tablespoon of olive oil in a well-seasoned cast-iron skillet.Add the sliced red onion and half a tablespoon of sea salt. Cook over medium heat, stirring often until soft, about 30 minutes.Once the onions are soft add the garlic, cook for a minute then add 1 tablespoon of balsamic vinegar. Stir quickly until the vinegar evaporates. The onions should be soft and sticky now.
Break 8 eggs into a large mixing bowl. Briefly whisk the eggs together. Add in the crumbled feta and thyme leaves. Season with salt and black pepper and stir.
Add the sweet potato and broccoli to the red onion. Pour the egg and cheese mixture over the vegetables. Then transfer the skillet to the oven.Cook for 30 minutes or until the frittata is cooked through but has a little wobble in the middle. Test with a dry knife, the knife should come out of the frittata clean.Serve warm or cold.
Eggs - I use medium, free-range eggs for this recipe.
Feta - Look for a good quality Cypriot feta, I always use full-fat.
Sweet Potato - I always peel the sweet potato, make sure when you cut it into chunks that they are all roughly the same size, this will ensure they cook at the same time and you don't end up with undercooked or mushy sweet potato.
Broccoli - I use purple sprouting broccoli for this recipe, I don't precook the broccoli. You can use regular broccoli if you want. If you do then I would steam the broccoli before adding it to the pan.
Whisking the eggs - Try not to over whisk the eggs, they just need a quick whisk. If you get too much air in there then the frittata will puff up in the oven and then deflate when you take it out.
Pan - My skillet measure in at 22cm/9inches. Make sure you use a stove to oven skillet, a well-seasoned cast-iron skillet works best.
Reheating/storing/freezing - If you have any leftovers they can be stored in the fridge for up to 2 days. You can reheat this if you want, however it is great cold too. Reheating may result in a slightly rubbery frittata. I don't recommend freezing frittata.
Nutritional Information - is approximate and is calculated using an online nutrition tool. It is based on one serving.
Measurements - I weigh all my ingredients using an electric scale, all measurements are metric. Cup measurements are approximate.