Prep and Sear Chicken: Pat chicken completely dry and season both sides with salt, pepper, and Italian seasoning. Heat 2 tablespoons of reserved sun-dried tomato oil in a large Dutch oven over medium-high heat. Sear chicken for 3-4 minutes per side until golden brown. Remove from pot, let rest for 10 minutes, then shred the chicken with two forks.

Build Flavor Base: Reduce heat to medium, add butter and diced onions to the pot. Cook for 8-10 minutes, stirring occasionally, until onions are soft and lightly caramelized. Add minced garlic and cook for 1 minute more until fragrant.

Create Tomato Base: Add drained sun-dried tomatoes (reserving a few for garnish if desired), tomato paste, remaining Italian seasoning, Dijon mustard, and honey. Cook for 5 minutes, stirring constantly, to deepen the flavors.

Blend and Simmer: Pour in the chicken broth and add the bouillon cube. Use an immersion blender to blend the mixture until completely smooth. Return the shredded chicken to the pot. Bring to a boil, then reduce to a gentle simmer and cook, partially covered, for 15 minutes.

Finish and Serve: Remove the pot from the heat. Stir in the heavy cream and grated Parmesan cheese until smooth. Add the refrigerated tortellini and fresh spinach. Return to low heat and simmer for 3-4 minutes, or until the tortellini is cooked through and the spinach has wilted. Season with salt and pepper to taste before serving hot.