Step 1

Cut the top end of the red onions. Make a cut in half without reaching the bottom end, make another cut in half again and repeat until you have four cuts. Repeat with the other onions.

Step 2

Place the onions in a bowl and drizzle with olive oil.

Step 3

Add the balsamic vinegar, mix, and let stand for 10 minutes.

Step 4

Place the onions in an oven-safe baking dish, and drizzle with the oil mixture. Season with salt and pepper.

Step 5

Bake for 30 minutes at 200°C/400°F. Remove the aluminum and return to the oven for 10 minutes.