Preheat oven to 220 degrees C
Place the broccoli, seeds, olive oil, oregano, salt, and pepper in a large bowl and mix until combined
Spread into an even layer on a large baking tray and roast for 15 minutes, until broccoli and seeds are beginning to brown
While the broccoli roasts, make the dressing by whisking all the ingredients and pour into the big bowl used for the raw broccoli
Once the broccoli has roasted, remove from the oven and place in the bowl with dressing and toss to combine
Let it stand for about 10 minutes to cool down and mix in the feta and cranberries
Serve immediately or place in the fridge to cool down completely and serve then