French Onion Crostinis

Directions

1. 1
   Peel onions and chop in half.
2. 2
   Lay each half of the onion flat side down and slice onion in 1/4 slices.
3. 3
   Separate layers of the slices so you end up with about 6 cups of half-moon shaped pieces from 3 medium size onions.
4. 4
   Heat butter in a large frying pan until melted and add onions.
5. 5
   Saute for 5-10 minutes until onions begin to soften.
6. 6
   Add salt, pepper, vinegar, and Worcestershire sauce and place heat on medium.
7. 7
   Cook onions for another 30 minutes or so, stirring often, until onions are very soft and cooked through.
8. 8
   While onions are cooking, preheat oven to 375 degrees F and line 2 cookie sheets with parchment paper.
9. 9
   While onions are cooking, slice baguette on the bias in slices a little less than 1/2 thick.
10. 10
    Spread one side of each piece of baguette with a thin layer of mustard and place on the cookie sheets, mustard-side up, fitting as many onto each pan as you can.
11. 11
    Once onions have caramelized, place some onions on top of each piece of baguette, enough to include onion in each bite.
12. 12
    You can add more or less to taste, depending on how many onions you chopped.
13. 13
    Sprinkle a tablespoon or two of grated cheese on top of the onions on each piece.
14. 14
    Bake crostinis in the oven for 15-20 minutes or until cheese has melted and begun to bubble.
15. 15
    You can also finish with a minute or two under the broiler, but keep a close eye on them to make sure they dont burn.
16. 16
    Serve warm!