Put a medium dutch oven on medium heat. Add in the olive oil and let it come to temperature for about 2-3 minutes.
Add in the diced onion, it should sizzle when it hits the oil. Cook the onion for about 4-5 minutes, stirring occasionally. You want it to soften but not brown, so lower the heat if you need to.
Season with salt to taste and add about 1/2 cup of the vegetable stock. Let the onion simmer in this until it becomes soft and transluscent, another 3-4 minutes. You're aiming to almost melt the onion into the oil, so you get all of the flavor but not big onion chunks.
When the broth has completely evaporated, add in the grated garlic and give it a quick stir. Then add in the sliced peppers and season again with salt as needed. Let these elements cook down for 1-2 minutes to let the peppers soften.
Add in the beans and the rest of the vegetable stock. Season with more salt and a few cracks of black pepper. Let this simmer for another 2-3 minutes.
Remove the soup from the heat and add the juice from one lemon and the dill. Stir to combine. Taste and season with salt, pepper and maybe a splash of red wine vinegar if you feel you need it.
Serve in a bowl with a toasted slice of bread, a sprinkle of feta and a few cracks of black pepper!