To a large bowl, add the turkey, egg, onion, almond flour, garlic, rosemary, thyme, salt, and pepper. Use your hands to mix everything together, until fully combined.
Measure out 1 1⁄2 tablespoons of mixture (or use a medium cookie scoop) and roll the mixture between your hands, forming approximately 30 meatballs. Place the meatballs on a plate.
Heat 2 tablespoons of oil in a large pan on medium heat. Add half of the meatballs to the pan and brown on all sides, about 5 to 8 minutes. Remove the first batch of meatballs to a plate, add another tablespoon of oil to the pan, and repeat with the remaining half of meatballs. Once the second meatballs are cooked, remove them to the plate as well.
Deglaze the pan by adding the chicken broth, and use a spatula to scrape up any bits off the bottom. Then add the Dijon mustard, maple syrup, and mayonnaise. Whisk everything together and let the sauce simmer until it's creamy. Add the meatballs back to the pan and warm through. Garnish with additional fresh chopped herbs before serving.