The onions should be cooked for 15 to 20 minutes with frequent turning until they soften. Then, turn the heat up to medium-high and incorporate the remaining butter and olive oil.

Once the onions begin to brown, stir continuously for a further fifteen minutes. 1 tablespoon salt and sugar should be added.

To get beautiful browning on the onions, heat for an additional 10-15 minutes. Then add the garlic and continue cooking for another minute.

Use the white wine to clean out the pot. Scrape the browned bits from the pot's sides and bottom before adding the wine.

Bring to a simmer the beef stock, thyme, and bay leaves. For a low simmer, reduce the heat and cover the pot. For around 30 minutes, cook. Remove the bay leaf before adding salt and black pepper to taste.

While the soup simmers, toast the French bread. Put a sheet pan in the oven and preheat it to 450 degrees.

The French bread pieces should be lightly brushed with olive oil on both sides before being placed in the oven to toast. No more than 5-7 minutes should pass.

After taking the bread slides out of the oven, top with shredded Gruyere and Parmesan. When it's almost time to serve, put them back in the oven for a few minutes so the cheese may bubble and start to brown.

Time to serve the day's soup. Pour the soup into each bowl, then add the cheesy bread to each bowl. It's done. Your onion soup will have a French flavor.