Ratatouille - Slow Cooker or Oven Vegetable Casserole, French Style

It’s summertime, and vegetables are available at very reasonable prices from our garden, neighbors, the grocery store, or the local farmers’ market. The summer squash and zucchini I see all around remind me that this is the perfect time to try one of Mom’s vegetable casserole dishes – a type of ratatouille.

It's a little different from the traditional dish, which normally contains eggplant. But that was one of the very few dishes that my usually non-finicky father absolutely refused to eat, so it was never served in our house. 

That's not to say that you couldn't include it yourself. Or just about any other vegetable of your choosing, for that matter. This recipe would be suited for just about any of them.

​The preparation is a cinch for this, and the results are delicious. The only drawback is that it calls for the use of the oven, and when the temperatures are climbing, that’s not the most convenient thing.  So it’s a good dish to make on one of those occasional, cool, rainy summer days here in New England, and/or to make it in quantity and freeze the extra for later. Or, of course, you can use your grill as well, if you have one and are familiar with using one that way. 

Or you can make this in a slow cooker if you have one, and simply pop the casserole into the oven for about 10 minutes to brown the top.  That saves on oven time and the extra heating of the kitchen. I actually love slow cookers in the summer.  I set mine up under cover on our patio or in the basement, and leave it to do its work without heating up the whole house. 

This recipe makes 6-8 generous servings and is great as leftovers for other meals, or for lunch during the week. The total cost for the meal with salad, pasta and bread is about $12, or approximately $1.50 per serving. 

NOTE: this dish can be made gluten free for those with celiac disease or gluten intolerance by serving it with rice pasta or rice instead of the whole grain pasta I suggest here. And, of course, I recommend brown rice instead of white rice. 

Here's the recipe:

Ratatouille (French-Style Vegetable Casserole)
​Makes approximately 8 servings
P​rep Time – Approx. 15 minutes
Total Start to Finish Time – About 90 minutes (4-6 hours in the slow cooker)
Total Recipe Cost - Approx. $8
Total per Person Meal Cost with tossed salad and bread - Approx.  $1.50-$1.75

Ingredients:
For the Recipe:
3-4 tablespoons olive or vegetable cooking oil
3-4 cloves garlic
2 large onions
4 large carrots (or other vegetable of your choice, such as eggplant)
2 medium to large zucchini
2 medium to large yellow squash
¼ cup grated Parmesan cheese
8 ounces cheddar cheese or 2 cups pre-grated
2 6-ounce cans tomato paste
2½ cups of water
1 teaspoon thyme 
½ teaspoon salt (or to taste)
½ teaspoon pepper (or to taste)

Ingredients for the Meal:
Ratatouille Casserole
1 Pound Whole Grain Rotini or Similar Pasta
OR
6-7 Cups of Cooked, Brown Rice
Tossed Green Salad
Whole Grain Bread (optional)

Recipe continues after photos

 Procedure:

1. Pre-heat the oven to 400° bake.
2. Peel and coarsely dice the onions. 
3. Cut off the tips of the 3-4 garlic cloves and peel them.  Cut or chop them into small pieces.
4. Wash the 2 each of zucchini and summer squash.  Cut off about 1 inch from the ends. Slice the squash crosswise into discs about ¼-inch thick.
5. Wash and scrub the 4 large carrots using a plastic brush or scrubber.  Or you may peel them if you like, but unless the peel is in very bad shape, there is no need. Cut off the ends and slice the carrots crosswise at an angle to create pieces about ⅛-inch thick.
6. Grate the cheese to make  2 cups.
7. Measure about 2 tablespoons of the oil into a frying pan over medium heat. 
8. Add the onions and cook them, stirring often, until they are almost translucent, about 5 minutes.
9. Meanwhile, scrape the two 6-ounce cans of tomato paste into a mixing bowl, using a rubber spatula. Add the 2½ cups of water and stir or whisk until well blended. Stir in the 1 teaspoon thyme, the ½ teaspoon of salt (to taste), and the ½ teaspoon pepper (or to taste).
10. Add the garlic to the frying pan and cook it, stirring often, for a minute or two.
11. Scrape the onion and garlic mixture into the tomato sauce and mix well.
12. Spread about 1 cup of the tomato mixture on the bottom of a large (9 X 12 or a bit larger) casserole.
13. Toss the cut up zucchini, summer squash, and carrots in a couple of tablespoons of olive oil. Or first layer them in the casserole, and then brush or spray each layer with some of the olive oil (see my blog post on cooking sprays here), followed by a sprinkle of the Parmesan cheese.
14. Top the layers with the remaining tomato sauce and the grated cheese.
15. Cover the casserole tightly with aluminum foil and place it in the oven for about 90 minutes. 
16. About 20 minutes before the end of the scheduled cook time for the, put on a large, covered pot of water to boil. Follow the instructions on the side of the pasta box to cook the pasta, which usually takes about 9-12 minutes for al dente.  Drain it in a colander and set it over a pan of hot water until you are ready to use it. Or reheat the rice in a covered microwave-safe container for 2-5 minutes on medium-low power
17. After about 90 minutes, check the vegetables for doneness.  They are ready when a knife or fork pierces them easily. Remove the foil cover and return the casserole to the oven for about 10 minutes, or until the cheese is browned. 
18. Remove the casserole from the oven.
19. Serve the ratatouille over a portion of pasta or rice and along with a tossed, green salad and the optional bread. ​