Use a large mortar and pestle to pound the Garlic Cloves and a pinch of Sea Salt to a fine paste.
Add the Pine Nuts and pound again until finely crushed. Add the Fresh Basil one cup at a time, pounding until fairly smooth each time. Repeat 4 times.
Then add in the Baby Spinach and pound until smooth.
Add in some finely grated Parmesan Cheese, some Olive Oil, and Pinch of Salt at a time. Keep mixing. Repeat a few times. Mix until well combined.
Cook the Bucatini in boiling salted water until just al dente according to the package instruction. Reserve some pasta cooking water. Drain the pasta and transfer to a large bowl.
Add in 2-3 large spoonfuls of Pesto Sauce and mix. Add more Pesto if desired.
Then add in some reserved pasta cooking water and mix again to the consistency that you like. Transfer to serving plates.
Sprinkle some Chili Flakes and grate more Parmesan on top. Or add some chopped Basil for garnish. Ready to serve!