Preheat your oven to 350°F.
Spray a 9x12 inch baking dish with non-stick cooking spray.
In a saucepan, melt butter over medium heat.
Add jalapeños and garlic, and sauté for 4 minutes.
Add heavy cream, half-and-half, salt, and pepper to the saucepan.
Bring this mix to a simmer.
In a large bowl, toss the sliced potatoes in the cream mixture until they're well-coated.
Layer them evenly in the prepared baking dish.
Sprinkle Parmesan cheese over the top.
Bake uncovered for 40-45 minutes until potatoes are tender and golden brown.