01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, combine ground chicken, sun-dried tomatoes, Parmesan, breadcrumbs, egg, garlic, parsley, oregano, salt, and black pepper. Mix gently until just combined.
03 - Form mixture into 16-18 small meatballs, about 1.5 inches each.
04 - Heat olive oil in a large skillet over medium heat. Sear meatballs in batches until golden brown on all sides, about 4-5 minutes total. They do not need to be fully cooked through.
05 - Arrange seared meatballs on the prepared baking sheet and bake for 10-12 minutes, or until cooked through to an internal temperature of 165°F.
06 - Meanwhile, in the same skillet, melt butter over medium heat. Add shallot and sauté for 2-3 minutes until softened.
07 - Stir in heavy cream, chicken broth, Dijon and whole-grain mustards. Bring to a gentle simmer and cook for 3-4 minutes, stirring frequently.
08 - Add Parmesan cheese and season with salt and black pepper to taste. Simmer for 2 more minutes until slightly thickened.
09 - Return baked meatballs to the skillet and coat in the sauce. Simmer together for 2-3 minutes to meld flavors.
10 - Garnish with fresh parsley if desired. Serve hot with rice, mashed potatoes, or crusty bread.