Ever so often my husband surprises me with a ratatouille. I have begged him to stop because it tastes as if the vegetables have bled to death, but he wont'. So...how do we keep the flavours in?
Ratatouille is one of those supposedly simple dishes which can be actually quite difficult to cook well. The main error in making ratatouille (and we suspect the problem with your husband's recipe) is that the vegetables are not cooked for long enough in oil enough to generate good flavour and instead are just stewed in the tomato sauce which will tend to leave the vegetables tasting a little washed out. Elizabeth David is the doyenne of rustic French cooking and it is worth checking the recipe in her book French Provincial Cooking. Nigella took this as her inspiration for the Ratatouille in How To Eat (p116).
As we now live in slightly more health conscious times, roasting the vegetables for ratatouille has become more popular as the vegetables will concentrate some of their flavours in the oven but will not absorb as much oil as with the traditional recipe. Cut the vegetables into 2 - 2 1/2 cm (3/4 - 1 inch) pieces and toss in olive oil then spread out in a roasting pan, season with salt and pepper and cover the pan with foil. Roast at 180c/350F for about 45 minutes, until the vegetables are soft, then uncover, increase the oven temperature to 200c/400F and roast for a further 15 to 20 minutes. Cook the tomato sauce separately in a saucepan then add the roasted vegetables and simmer for about 15 minutes to allow the flavours to come together.