Heat a large frying pan on a medium heat, add 2 tablespoons of olive oil and gently fry the green peppers for 10-15 minutes until they start to soften then place in a large bowl and set aside
Repeat this step with the courgettes, then the aubergines and finally the tomatoes, adding more olive oil when necessary and cooking each batch of vegetables separately for 5-10 minutes until lightly browned and softened then place in the large bowl
Add all the vegetables from the bowl, rosemary and thyme to a large frying pan on a low heat, season with salt and pepper, put the lid on and simmer gently for 45 minutes, stirring occasionally and adding a little more water if necessary (if you don't have a frying pan with a lid, a large saucepan with a lid will do fine)
To serve, stir through the pitted olives, drizzle over the garlic oil and sprinkle the basil leaves on top
Freeze any leftovers for another day
Recipe by Cook Low FODMAP at https://cooklowfodmap.com/low-fodmap-ratatouille/