I don't remember ever making French Onion Soup so I don't know if this is a "normal" French Onion Soup. I checked the Food Network and the three chefs, whose recipes I read over, had variations on the theme but none used the Dijon mustard that was in Donna's soup. I questioned my husband on this. Mustard did not seem to blend in but it did, when it was cooked. The kind of alcohol differed in each recipe so I felt better not having brandy in the house and subbing in wine.
I chose not to serve the cheese sandwich with this. Instead I made a pasta dish with was similar to pesto but it was mixed with cottage cheese. That with a green salad made a complete dinner.
I think, I didn't brown the onions enough, judged by the color of the soup, and the mustard clumped up, in places. The pieces of onion were very long and difficult to eat neatly.
Bottom line - we liked it, despite my minor unplanned alterations.
Showcase Your Talent Thursday