Put potato cubes, sliced onion, and garlic cloves in a large bowl. Add around 1 tablespoon olive oil, salt, pepper, dried basil, and rosemary. Toss.
Put zucchini cubes in another bowl. Add around ½ a tablespoon of olive oil and salt.
Spread the vegetables on baking trays lined with baking sheets. You can bake the vegetables in separate baking sheets one by one. Or, together on the same tray.
If baking separately, bake potatoes in a preheated oven at 200°C (400°F) for around 30 minutes or until the potatoes are nicely cooked and get golden brown edges. Zucchini is needed to be baked at 200°C (400°F) for around 25 minutes or until its edges turn brown.
Else, if baking together, bake potatoes for around 10 minutes, and then add zucchini. Bake them together for another 25 minutes or until the vegetables are roasted well.
Boil vegetable stock in a pot. Add roasted potatoes, onion, zucchini, garlic pulp, and red chili flakes. Mix everything and cook for 1-2 minutes.
Blend with a hand blender until smooth and creamy. Check and adjust the seasoning.
Pour into serving bowls. Add some olive oil, crushed pepper, and chili flakes on top. Enjoy!