Preheat your oven to 400°F (200°C).
In a large frying pan, melt 1 tbsp butter with 1 tbsp vegetable oil over medium-high heat.
Add the chicken thighs and fry until the skin is very crisp and brown on both sides.
Drain and place the chicken into a 9×13 baking dish.
Drain the fat from the pan and melt the remaining 2 tbsp butter over medium heat.
Add chopped garlic and cook for 1 minute, then add spinach and sauté until it shrinks.
Whisk in chicken broth, heavy cream, flour, and grated Parmesan.
Adjust with lemon juice to taste, and cook for 2-3 minutes until the sauce thickens.
Arrange the parboiled baby potatoes between the chicken thighs in the baking dish.(Tip: halve larger potatoes or quarter smaller ones for faster cooking.) Pour the spinach and cream sauce around the chicken and potatoes.
Bake in the preheated oven for 25-30 minutes or until the chicken reaches an internal temperature of 175°F and the potatoes are tender.
Remove from the oven and serve hot and enjoying!