Prep all your vegetables by chopping the bell peppers, zucchini, and sweet potato into rustic, uneven chunks. Set aside.
Heat your large cast-iron skillet over medium-high heat until it’s hot and shimmering. Pour in the olive oil, swirling to coat the bottom evenly.
Add the sweet potato cubes to the skillet in a single layer. Let them cook undisturbed for about 8 minutes, listening for a gentle sizzle, until the edges start to brown and smell sweet.
Toss in the bell peppers and zucchini, spreading them out evenly. Continue cooking, stirring every few minutes, for another 5-7 minutes until the vegetables develop golden, slightly charred edges and become tender.
Add the minced garlic to the skillet during the last minute of cooking. Stir quickly until fragrant and slightly toasted, about 30 seconds to a minute.
Season generously with salt and pepper, tasting as you go. Continue cooking until all vegetables are caramelized with smoky, charred spots, and tender inside.
Remove the skillet from heat and let it sit for a couple of minutes to allow flavors to settle and juices to redistribute.
Sprinkle freshly chopped herbs over the top for a bright, fresh contrast. Serve directly from the skillet for a rustic presentation or transfer to a plate.