Spinach & Herb Turkey Burgers with Portobello "Buns"
This low-carb burger replaces the typical bun with roasted portobello mushroom caps. Creamy tzatziki and crisp sliced red onion add texture and flavor to this easy Greek-inspired burger recipe. Form into four 4-inch patties. Place on the prepared baking sheet. Brush oil all over the portobellos, then sprinkle with the remaining 1/4 teaspoon each salt and pepper. Place the mushrooms on a wire rack placed over another large rimmed baking sheet....