Wash and dry all produce. Preheat the oven to 400 degrees. Have, peel, and dice the onion. Mince the garlic. Finely dice the zucchini. Finely chop the mushrooms.

Heat a drizzle of olive oil in a large pan over medium-high heat. Add the onion and garlic to the pan. Cook, tossing, for 2-3 minutes, until softened. Add the Southwest seasoning and cook an additional 2 minutes. Season with salt and pepper. Add the tomato paste and stir to coat. Add the honey, 1 cup water, and half the vinegar to the pan. Simmer 10 minutes, until thickened. Season with salt and pepper.

While the sauce simmers, heat a large drizzle of olive oil in another large pan over medium-high heat. Add the mushrooms and zucchini to the pan. Cook, tossing, for 5-7 minutes, until softened. Stir the seitan and sauce into the pan. Cook another 2-3 minutes, until heated through.

Toast the buns: Place the buns in the oven to toast 3-5 minutes until golden brown.

Toss the salad: Toss the arugula in a medium bowl with a drizzle of olive oil and the remaining vinegar. Season to taste with salt and pepper.

Assemble the sloppy joe: Fill the buns with as much seitan sloppy joe filling as possible. Serve the arugula salad alongside and enjoy! TIP: Leftover filling makes a great pasta sauce for another night!