Preheat oven to 425°; peel then cut sweet potato into ½-inch thick, 3-inch long sticks, place on a sheet pan, drizzle with 1 tbsp oil + salt/pep + toss to combine; bake 15 min, turn fries over + bake til browned + tender, about 10-15 min

Meanwhile, heat lightly oiled skillet over med; cook burgers 5 min on one side, then flip over + cook 2-3 min more til browned + cooked through

Cut onion in half from root to stem + peel; thinly slice ½ onion, set aside

Toast 2 buns til warm + golden

Top buns with burgers, a few onions + handful of spinach; serve fries on the side (Tip: enjoy remaining spinach as a side salad with oil, vinegar, salt + pep)