Heat the olive oil in a large skillet or Dutch oven over medium-high heat.
Add the minced garlic and diced onion, and sauté for 2 minutes, stirring frequently until fragrant.
Add the zucchini and continue to toss for another 2 minutes.
Finally, add the green pepper and tempeh cubes, and cook for 5 more minutes, tossing occasionally until the tempeh is lightly browned.
Pour in the chopped tomatoes, vermouth, and add all the remaining herbs and seasonings.
Stir everything together well to combine.
Bring the mixture to a gentle boil, then reduce the heat to low, cover, and let it simmer for about 10 minutes. The goal is for the sauce to become fragrant and slightly thickened, while the vegetables still retain a bit of a crisp-tender bite.
Taste and adjust seasoning with more salt and pepper if needed.
Serve immediately while hot. This dish can also be made ahead; simply cover and chill for up to 24 hours, then reheat slowly on the stovetop until piping hot.
While delicious with brown rice, this dish is also fantastic served over quinoa, creamy polenta, or with a side of crusty bread for dipping.
