Bring a large pot of salted water to a rolling boil. Add the pasta and cook until just al dente, about 8 minutes. Drain and set aside, reserving a splash of pasta water.
In a deep skillet, melt the butter over medium heat until it starts to bubble and smells nutty, about 1 minute. Add the chili flakes and toast briefly, releasing their smoky aroma.
Pour in the heavy cream and gently simmer, stirring constantly, for about 2-3 minutes until it warms and thickens slightly, filling the kitchen with a rich, dairy scent.
Gradually add the shredded cheddar cheese in small handfuls, stirring constantly until each addition melts into a smooth, glossy sauce. If the sauce thickens too much, stir in a splash of reserved pasta water to loosen it to your desired consistency.
Mix in the smoked paprika for a smoky depth, then season generously with salt and pepper. Taste and adjust seasoning as needed, ensuring the sauce is bold and spicy.
Add the cooked pasta directly into the cheese sauce, folding gently with a wooden spoon until every piece is coated with the cheesy, spicy mixture. Let it cook together for 2 minutes to meld the flavors and create a bubbling, gooey dish.
Remove from heat and let sit for a couple of minutes—this helps the cheese sauce thicken slightly and intensifies the chaotic, cheesy aroma. Serve hot, with extra chili flakes or cheese on top if desired.
