Preheat the oven to 375°F. In a medium-sized mixing bowl, beat the softened cream cheese, garlic powder, and sour cream together until the mixture becomes smooth and fluffy. Incorporate the shredded cheddar cheese, ¾ cup Parmesan cheese, and diced jalapeños, blending thoroughly. Transfer this creamy mixture into an 8x8 baking dish, spreading it evenly.