Sauté the chopped onion in olive oil for 3 minutes over medium heat. Add the garlic and sauté for another 2 minutes, or until the garlic begins to brown. Remove from heat. Transfer the onions, garlic, and oil to a large bowl to cool down.
Once the onions are cool to the touch, add the ground turkey, salt, pepper, and herbs into the bowl. Using your hands, gently mix everything until well combined. You want the herbs mixed in without overworking the meat (which would make the burgers tough).
Form the meat into patties. Here's a burger patty tip: use your fingers to form a slight indentation in the middle of the patties. When burger patties cook, the meat contracts from the edges. Having the middle part slightly thinner than the edges when raw will help the patties finish with a more even shape (less bulge in the middle).
Cook on a hot grill or in a hot cast iron frying pan for 5-6 minutes per side, until cooked through (165°F if using a meat thermometer). If using a grill, coat the grill grates first with a little vegetable oil. If using a frying pan, put a little oil in the pan first to help keep the burgers from sticking.
Serve with toasted buns, and the accompaniments of your choice—sliced onions, lettuce, sliced tomatoes, bacon, mayonnaise (especially good with mayo), mustard, relish, ketchup.