Peel the onions and slice them into long, thin strips (you can take the opportunity to watch a tearjerker movie at the same time).

Melt 3 tablespoons of the butter in a hot skillet, taking care not to burn it. Use medium-low heat.

Add the onions and season with salt and pepper to taste.

Cook the onions until they become translucent. The goal is for them not to brown, or at most, turn a light golden color. When in doubt, lower the heat further, even if you have to wait longer to reach the right cooking point.

Mix the flour with the onions and stir well to distribute the powder evenly. Cook for a couple of minutes.

Add the alcohol, stir, and cook for a couple more minutes.

Add the broth, cover, and cook for 25 minutes over low heat.

Take this time to preheat the oven to 200 degrees C.

Check and stir the onion broth occasionally to be 100% sure the floured pieces do not stick.

Use this time to slice the baguette. Make sure the slices are not too thin so they hold up well during cooking.

Spread the remaining butter onto the slices.

Peel the garlic clove and rub it against each piece of bread as if you were spreading something with a knife. The idea is for them to absorb the flavor. You can make small cuts on the surface of the clove so it opens up under pressure against the bread. You can also crush it slightly with a mallet to release more flavor.

Top each slice of bread with a generous pile of shredded cheese.

Once the soup's cooking time has passed, divide it into individual oven-safe bowls and place slices of bread in each. You can place the slices on top of the served liquid, or place one at the bottom before pouring the broth and the rest on the surface.

Place the bowls in the oven. Close and increase the heat to 215 degrees C for 4 minutes, or until you get a nicely gratinated onion soup.

Remove from the oven and serve immediately.