Heat Oil in a SaucePan, add minced garlic. Saute for 1 minute and add chopped tomatoes. Add Chilli Powder, Onion Powder, Oregano Powder and Handful of finely chopped basil. Season with salt and pepper.
Add 120ml of water, cover with shatterproof lid and cook in medium flame until all the tomatoes get mushy and tomato sauce comes together. This can take about 10 minutes.
Trim the top of the Peppers and core. Trim the ends of aubergines and courgettes. Peel the onions.
Meanwhile,adjust the blade slicer in the mandoline slicer to 1/16inch and slice the aubergines,courgettes,onions thin.
Cut the peppers medium to thin as desired using a knife. We like it a bit chunkier.
Preheat the oven to 190 degree C.
Spread 3/4 portion of prepared tomato sauce into the bottom of a cast iron skillet. Alternate the slices of vegetables in order of aubergines, courgettes, peppers and onions starting from the outer circle, finishing to the middle.
Pour the remaining sauce over the top.
Drizzle with Olive Oil , season with salt . Cover the pan with aluminium foil and bake for about 40-45 minutes at 190 degree C until roasted and tender. Just ensure the vegetables still retain their structure and they do not brown at the edges.
Grate lemon zest and if you like some parmesan cheese too on the top.
Serve Ratatouille warm with some bread or couscous!