Japanese Sesame Spinach Salad (Horenso no Goma-ae)

Start by filling a pot with enough water to cover the spinach, add 1 tsp salt and bring to a boil. While it's is heating up, cut off the ends of the stems of 250 g spinach and wash thoroughly in a cold bowl of water to remove the dirt.
Remove the spinach from the water and cut it into three parts, the thick stems, the middle part (thinner stems with some leaf) and the leaves. Preferably tie each type in bunches. (Optional)
Prepare a bowl of cold water and set it next to the stove.
Once the water in the pot is boiling, add the thick stems and allow them to boil for 1 minute.
Next, add the middle part and boil together with the stems for 45 seconds.
Finally add the leaves and boil everything together for 30 seconds.
Remove the spinach from the water and transfer straight to the bowl of cold water to stop the cooking process.
Take a mixing bowl (big enough to add the spinach) and add ¼ tsp salt, ½ tbsp soy sauce, 2 tbsp ground sesame seeds, 1 tbsp light brown sugar, ½ tbsp white sesame seeds, ½ tbsp dashi stock. (If you don't have dashi you can use an equal amount of water instead.) Mix well.
Remove the spinach from the bowl, gently squeeze out the excess water and add it to the bowl of sauce. Mix thoroughly until evenly coated.
Serve and enjoy!