Cube the eggplant and add it to a colander sitting in the sink. Sprinkle a teaspoon of salt over it, toss and allow it to sit while you chop the vegetables. Salting the eggplant draws out the water and firm it up, which helps it not be as mushy.
Add the olive oil to a large (wide) pan and turn the heat on medium.
When the oil is hot, add the onion and cook for five minutes.
Add all of the peppers and cook for three minutes.
Add the zucchini, yellow squash, garlic and spices and cook for three minutes.
Add the eggplant and tomatoes and cook for two minutes, uncovered.
Turn the heat down to medium-low, cover and cook for five to seven minutes, stirring frequently. You want the vegetables cooked through but not mushy.
Turn off the heat and add the fresh parsley.
Stir to combine and taste to adjust the seasonings.