Cut the guanciale into thin strips and remove the rind
Render the guanciale in a pan over medium heat until crispy and golden, allowing the fat to melt out
Remove the crispy guanciale and set aside, keeping half of the rendered fat in the pan and setting half aside
Add freshly ground black pepper to the pan with the remaining fat
Cook the tonnarelli in lightly salted water until al dente
Mix grated Pecorino Romano with some rendered guanciale fat and a splash of hot pasta water in a bowl until it forms a smooth, creamy paste
Transfer the cooked pasta directly to the pan with guanciale fat and pepper using tongs, saving some pasta water
Finish cooking on high heat, tossing and adding pasta water if needed
Turn off heat and let cool for 1-2 minutes
Add the pecorino cream and mix vigorously until the pasta is fully coated
Add more black pepper and toss in half of the crispy guanciale
Plate and top with remaining guanciale, pecorino, and black pepper
