Finely chop the onion, mince the garlic cloves, slice the mushrooms, dice the zucchini, chop the fresh tomatoes, and chop the sun-dried tomatoes. Having everything prepped and ready ensures the quick-cooking vegetables won't overcook while you're chopping. This is especially important for a skillet dish where timing is tight.

Heat the olive oil in a large skillet over medium heat. Add the chopped onion and sliced mushrooms, cooking for 5-6 minutes until the mushrooms release their moisture and the onion becomes translucent. The mushrooms will develop a deeper flavor as they cook down. Add the minced garlic and cook for another minute until fragrant, being careful not to burn it.

Add the cauliflower rice, diced zucchini, and chopped fresh tomatoes to the skillet along with 3/4 cup vegetable broth and dried oregano. Stir well to combine and bring to a simmer. Cook for 5-6 minutes, stirring occasionally, until most of the broth is absorbed and the vegetables are tender. I like to let the broth reduce slightly so the flavors concentrate rather than being diluted by excess liquid.

Add the spinach and chopped sun-dried tomatoes to the skillet, stirring to combine. Cook for 3-4 minutes until the spinach is wilted and fully incorporated. The sun-dried tomatoes add a concentrated, slightly sweet Mediterranean flavor that brightens the entire dish.

Taste the skillet and season with salt and black pepper to your preference. Stir one final time to distribute the seasonings evenly throughout. Transfer to serving bowls or plates and enjoy warm. I recommend tasting before adding salt, since the vegetable broth and sun-dried tomatoes already contribute some saltiness.