Go Back
This potato, tomato and zucchini casserole incorporates both white and sweet potatoes is delicious and highly nutritious. Plus, it adds loads of color to your plate
Print Recipe
5 from 1 vote

Two Potato, Tomato & Zucchini Au Gratin

This sweet potato, tomato and zucchini au gratin is delicious and highly nutritious. Plus, it adds loads of color to your plate.
Author: Heather Mangieri, RDN


  • 1 Large Sweet Potato
  • 1 Large White Potato
  • 1 Medium Zucchini
  • 1 Medium Onion
  • 1 Large Tomatoe
  • 2 tsp Olive Oil
  • 1 tbsp Rosemary, dry
  • 1/8 tsp Salt
  • 1/4 tsp Pepper


  • Preheat oven to 375 degrees. Spray a 9 x 13 inch glass baking dish with vegetable oil. Set aside.
  • Make Caramelized Onions- Heat the olive oil in a medium saucepan. Slice the onion thin, in circles. Add the onion slices to the oil, spreading the onions out in the pan to coat. Cook onions for 5-7 minutes until tender, stirring frequently, Transfer the caramelized onions to the baking dish, creating an even layer on the bottom.
  • Using a sharp knife or mandolin, slice the tomato, sweet potato, white potato and zucchini thin. Arrange the sweet potato, zucchini, white potato and tomato in overlapping layers in the glass baking dish, covering the caramelized onions.
  • If the middles slices of the tomato, sweet potato or white potato are too large, slice them in half and use the 1/2 piece to layer. Once done layering, stuff the extra vegetable slices into the dish to fill gaps.
  • Sprinkle the top with Parmesan cheese, thyme, salt and pepper. Add additional salt and pepper as desired. (Remember that the sodium content in the nutritional analysis is based on only 1/8 tsp salt.
  • Cover with foil and bake for 45 minutes. Remove foil and bake an additional 10 minutes or until cheese is slightly browned.


  • Recipe Makes: 6 servings
  • Nutrition Information (per serving): 120 calories, 20 grams carbohydrate, 3 grams fiber, 4 grams protein, 3 grams fat, 1 g saturated fat, 140 mg sodium, 6% DV for calcium, 6% DV for iron, 10% DV for potassium.
  • Meal Planning Servings- 2 CHO; 0 PRO; 0.5 FAT