In a large mixing bowl, combine ground turkey, ground chicken, grated Parmesan, garlic, Italian seasoning, and crumbled bouillon cube. Add in red chili pepper flakes, chopped cilantro, and freshly cracked black pepper to taste. Using your hands, gently mix until everything is well integrated. Form the mixture into medium-sized meatballs, about two inches in diameter.

Heat olive oil in a large skillet over medium-low heat. Once the oil is shimmering, carefully place the meatballs in the skillet, making sure not to overcrowd them. Cook the meatballs for 8-10 minutes, turning occasionally, until they are beautifully browned on all sides and cooked through, checking that the internal temperature reaches 165°F (75°C). Remove the meatballs and set aside.

In the same skillet, reduce the heat slightly and add butter. Allow it to melt, then introduce minced garlic and sauté for about 1 minute until it becomes fragrant, but not browned. Next, add chopped onion, cooking until it's translucent and softened, about 4-5 minutes.

Stir in the sun-dried tomatoes and let them cook for 1-2 minutes. Pour in the vegetable broth, scraping any browned bits from the bottom of the pan. Allow the mixture to simmer for about 3-5 minutes until the sauce slightly reduces.

Lower the heat to a gentle simmer and pour in the heavy cream, stirring well to combine. Let it simmer for another 2-3 minutes until the sauce is slightly thickened and creamy. Taste and season with salt and pepper according to your liking.

Add the baby spinach to the sauce, stirring until it wilts. After a minute, sprinkle in the remaining Parmesan cheese and stir until it melts completely.

Carefully add the browned meatballs back into the skillet, nestling them into the creamy sauce. Serve over steamed vegetables, zucchini noodles, or your favorite pasta.