Preheat oven to 425 degrees. Line a rimmed baking sheet with parchment paper.
Add the creamer potatoes, mushrooms, crushed garlic, lemon zest and chopped butter to the prepared baking sheet. Toss to combine. Roast for 30 minutes.
While the potatoes and mushrooms are roasting, prepare the chicken. Sprinkle the chicken breasts with smoked paprika, a dash of sea salt and ground pepper.
In a large cast iron skillet or dutch oven, heat the olive oil over medium heat.
Add the chicken breasts and cook for 5 minutes each side until the chicken is seared. Remove from skillet and set aside.
Add the shallots, baby zucchini, chopped sage, chives and crushed red pepper flakes to the hot skillet. Sauté until the shallots are golden and caramelized, about 10 minutes.
Add the white wine to deglaze the pan. Simmer for 1 minute.
Add the chicken broth and half + half to the skillet. Bring to a simmer over medium heat, stirring frequently.
Stir in the lemon juice and spinach. Add the roasted potatoes, mushrooms, garlic and any butter sauce to the skillet. Top with the seared chicken breasts and sprinkle with grated Parmesan.
Transfer the skillet to the oven and bake for 20 - 25 minutes until the chicken is cooked through.