Beetroot soup with feta, radish & croutons

Blitz this vibrant vegetarian soup to a smooth consistency, then serve hot or cold, with raw radishes and toasted sourdough for added crunch

2 tbsp olive oil
1 large onion, finely chopped
2 garlic cloves, crushed
1kg fresh beetroot, peeled and diced (wear rubber gloves to stop your hands turning pink)
1½ l vegetable stock
½ small loaf sourdough bread, diced into large croutons
100g radishes, finely sliced
100g feta, crumbled

Heat 1 tbsp oil in a large saucepan and add the chopped onion, frying for 5 mins until slightly softened. Add the garlic, stirring to combine for 1 min, then toss in the beetroot and cook for 15 mins.
Pour in the stock and bring to the boil. Once boiling, reduce the heat and simmer uncovered for 30 mins or until the beetroot is tender. Season well and leave to cool a little before blending.
Meanwhile, heat the grill to high and put the sourdough croutons on a baking sheet drizzled with the remaining 1 tbsp oil and toast until golden. Whizz the soup until smooth using a hand blender.
If serving the soup chilled, leave to cool completely and chill for a couple of hrs before serving. If serving hot, warm through in the pan for 2-3 mins. Serve in bowls or mugs with the croutons, radishes and crumbled feta scattered over. ???