Combine all ingredients (except noodles) into a food blender and blend until just about smooth. Keep a little texture in the sauce. Place blended ingredients into a saucepan and heat.
Bring 5 cups water to the boil. Add noodles and separate with a fork as you are adding them. Udon noodles contain salt, so the water does not need salt added to it. The noodles will be cooked within 8 minutes. Break one noodle in half to see if it is cooked. Drain noodles and place into a bowl.
Pour warm pesto sauce on top of noodles in a bowl and fold through. Serve garnished with a few more pine nuts on top.