Heat your oven to 220°C and place a large,lined baking sheet inside (you may need 2 sheets,depending on the size of your oven).
Keeping the vegetables separate,toss them in olive oil. Set a countdown timer to 50 minutes.
Place the pumpkin and onion on the baking sheet,leaving lots of space between the vegetables,and place the baking sheet in the oven.
When the timer reaches 40 minutes to go,add the carrots and fennel to the baking sheet. With 25 minutes to go add the broccoli and cauliflower,and with 20 minutes to go add the peppers.
Brush the pita breads with more oil and add those to the sheet in the last 10 minutes to warm through.
For the whipped feta,combine all the ingredients except the pepper and chilli in a food processor and blend until smooth.
You can add a little water or milk to adjust the texture,depending on the firmness of your feta.
Transfer to a bowl,drizzle with olive oil and scatter with chilli powder and ground pepper. Serve with the vegetables and pita bread.