Peel and dice the Yukon Gold potatoes into uniform cubes for even cooking.
In a large pot, bring water to a boil. Add the diced potatoes and cook for 10-12 minutes or until tender. Drain and set aside.
In a large skillet, melt the butter over medium heat. Add the finely chopped onion and sauté for about 4-5 minutes until softened and translucent.
Stir in the heavy cream and chicken broth into the skillet with the onions. Bring the mixture to a gentle simmer.
Add the garlic powder, paprika, salt, black pepper, and cayenne pepper (if using) to the skillet. Mix well to combine.
Gently fold the cooked potatoes into the skillet, ensuring all potatoes are well-coated in the sauce. Simmer for another 10 minutes, allowing the sauce to thicken slightly.
Preheat your oven to 350°F (175°C). Transfer the potato mixture into a baking dish.
Sprinkle the shredded cheddar cheese evenly over the top of the potatoes.
Bake in the preheated oven for 15-20 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let it cool for a few minutes. Garnish with freshly chopped parsley before serving.