Preheat the oven to 375 degrees. Coat a small baking dish with cooking spray.
Bring a medium saucepan of salted water to boiling over high heat. Add the broccoli florets and cook for 1-2 minutes or until bright green.
Immediately drain the water and transfer the broccoli florets to a large bowl of ice water. Let cool, then drain and place the broccoli on a clean tea towel or paper towel and pat dry.
Melt the butter in a medium saucepan over medium heat. Add the onion and cook for 2 minutes, stirring frequently. Add the paprika and garlic powder and continue to cook, stirring often, for 1-2 minutes.
Gradually whisk in the milk and cook, stirring often, for 3 minutes, or until it has thickened and coats the back of a spoon.
Gradually whisk in 1 cup of the cheddar cheese and the cream cheese then season with sea salt and freshly cracked pepper, to taste. Remove from the heat.
Toss the broccoli florets in the sauce and stir until evenly coated. Pour cheesy broccoli into the prepared baking dish.
Top evenly with the remaining ½ cup of cheddar cheese then sprinkle the crushed crackers on top.
Bake for 20-25 minutes, until casserole is bubbly and the cheese is melted.