Wash and dry all produce. Preheat the oven to 425 degrees. Peel the sweet potatoes and cut into 1/2-inch sticks (like French fries). Toss on one side of a baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Place in the oven for about 25 minutes, tossing once, until golden brown and crispy.

Meanwhile, core, seed, and dice 1 tomato. Thinly slice the other tomato. Halve, peel, and thinly slice the onion. Drizzle the portobellos with olive oil, and season on all sides with salt and pepper. Place on another baking sheet with the sweet potatoes and bake 10-12 minutes, until tender.

Meanwhile, heat a drizzle of olive oil in a medium pan over medium heat. Add the onion and diced tomato. Cook, stirring often, until jammy, for 10-15 minutes. Add a splash of water if the jam becomes too thick. Season with salt and pepper.

While the jam cooks, halve, pit, and thinly slice the avocado. Halve the buns, and place in the oven to toast about 5 minutes.

Assemble the burgers: Spread the buns with mayonnaise and the tomato onion jam. Top with the portobellos, sliced tomato, and a few slices of avocado. Serve with the sweet potato fries on the side. Enjoy!