Soak dried chickpeas in a large bowl of cold water for at least 12 hours (up to 24). Drain and rinse well before using.
Warm 2 tablespoons of the olive oil in a large heavy-bottomed pot over medium heat. Add the diced onion and cook gently for 8–10 minutes until soft and translucent — not browned. Add the crushed garlic and cook for another 2 minutes.
Add the soaked, drained chickpeas to the pot along with the water, bay leaves, and remaining olive oil. If using rosemary or oregano, add it now. Bring to a gentle boil, skimming any foam that rises in the first 10 minutes.
Reduce heat to the lowest setting where the soup still shows a few lazy bubbles. Prop the lid slightly ajar. Cook for 2½–3 hours, checking every 45 minutes. Add water if level drops below the chickpeas. You are looking for completely tender chickpeas and a broth that has thickened and turned a pale, creamy gold.
Remove the bay leaves (and rosemary if using). Add salt and several grinds of black pepper. Squeeze in the juice of one lemon, stir, and taste — then almost certainly add more. Remove from heat and drizzle over another generous pour of raw olive oil. Stir once, gently.
Rest the soup 10 minutes off the heat before ladling. It thickens slightly as it rests and the flavors settle.
Ladle into deep bowls. Finish each bowl with another pour of olive oil, cracked black pepper, and a lemon wedge on the side. Serve with crusty bread, olives, and raw onion at the table.