Preheat your oven to 350°F (175°C). Cook the elbow macaroni according to package instructions until al dente, then drain and set aside.

In a large saucepan, melt the butter over medium heat. Add the flour and whisk continuously for about 2 minutes to create a roux.

Gradually pour in the milk, whisking constantly to avoid lumps. Continue cooking and stirring until the mixture thickens, usually about 5-7 minutes.

Reduce the heat to low, then add the shredded cheddar and Pepper Jack cheeses. Stir until the cheeses are completely melted and the sauce is smooth.

Season the cheese sauce with salt, black pepper, and paprika. If you like it spicier, add the chopped jalapeños and stir to combine.

Add the cooked macaroni to the cheese sauce, ensuring the pasta is well coated.

Transfer the mac and cheese mixture into a greased baking dish.

Sprinkle breadcrumbs evenly over the top for a crunchy crust.

Bake in the preheated oven for about 20-25 minutes or until the top is golden brown and the cheese is bubbly.

Allow the Pepper Jack Mac and Cheese to cool slightly before serving. Enjoy the creamy, spicy goodness!