Steps

1. Boil the macaroni in water with an **approx. 1% salt concentration**.
   🕒 00:41
2. Make fine horizontal cuts into the onion. **This is the key!** Horizontal cuts prevent the onion from tearing too much.
   🕒 00:56
3. Make thin cuts into the onion, leaving the root end intact.
   🕒 01:09
4. When dicing the onion, don't try to cut it all at once; cut it in 3-4 batches.
   🕒 01:43
5. After making horizontal cuts, repeat the vertical cutting process up to the cut sections.
   🕒 01:50
6. When finely dicing the onion, cut with a single smooth motion rather than a sawing motion. **This is the key!** Sawing can easily crush the onion, so be careful.
   🕒 02:02
7. Lightly toast the cake flour in a pot.
   🕒 02:13
8. Toast for **1 to 2 minutes** to eliminate the raw flour taste.
   🕒 02:16
9. Add milk and break down any small lumps of white sauce until smooth.
   🕒 02:32
10. Mix to create a smooth white sauce by spreading out the lumps.
    🕒 02:43
11. Use the flat side of a spatula to break down and spread any solidified white sauce.
    🕒 02:49
12. Lightly spread and flatten the white sauce. **This is the key!** To ensure the sauce on the spatula doesn't burn, avoid getting sauce on it during this process for a clean finish.
    🕒 03:01
13. If the sauce is still cold, it means there's excess moisture, so continue to simmer.
    🕒 04:47
14. Taste the white sauce and adjust the salt.
    🕒 05:20
15. Coat a frying pan with oil and heat it thoroughly over **medium-low heat** until it's simmering.
    🕒 05:27
16. Sear the chicken well to get a nice brown crust. **This is the key!** If the chicken's moisture isn't removed, it won't brown and will end up being boiled.
    🕒 05:59
17. Once the chicken and vegetables (like shimeji mushrooms) release their juices, simmer over very low heat to prevent the soup from becoming cloudy. **This is the key!** Simmering over low heat, just enough for gentle bubbling on the surface, is crucial.
    🕒 07:33
18. Don't overcook the shimeji mushrooms; use them whole.
    🕒 07:57
19. Bring the water for the consommé soup to a boil, then cover and simmer over **medium heat** (around setting 3).
    🕒 08:35
20. Taste the consommé soup and adjust the salt.
    🕒 08:42
21. Once the gratin filling is hot, top with cheese and let it melt to finish.
    🕒 08:52