I like to keep a repository of "happiest memories" to draw upon in a pinch. One of those memories is as clear as a picture in my mind: me and a very dear friend of mine sitting on a bench in front of a historic movie theater on a fall day in Iowa City. We were eating sandwiches, and the sun was shining, and it was one of those perfect beginning-of-fall days that is chilly but not cold, and the sunlight is bright but softened, and I felt totally free. My sandwich had roast beef and caramelized onions, and I was so happy then.

Now that I am not a student, I find myself wildly jealous of the back-to-schoolers with their backpacks and sense of the new and the promise of knowledge. I also find something a bit romantic about sandwiches wrapped up in waxed paper and packed in brown paper sacks. I took the roast beef and the caramelized onions of my "happiest moment" sandwich (can't go wrong with them), added watercress, and just a few thin slices of sharp New York cheddar cheese. Caramelized onions take a bit of time, but this makes more than you need, and you can use the rest to garnish a red lentil soup.  Is this sandwich healthy? Well, it isn't a California-style veggie sandwich. But when you are eating something this powerfully delicious, you don't need a lot. I took a big slice of pumpernickel and cut it in half to make the sandwich more diminuitive, and served it with one of the sweet and very crisp first apples of the season. Seek out the ginger golds at your farmer's market, if you can. Standing in line, eyeing the wildflowers in the next stall, and chatting with the farmer, who knows, you may be making one of your new happiest memories. --Sarah McColl

The Best Roast Beef Sandwich
Serves 1

2 onions, sliced thin
1 tbsp. olive oil
1 tbsp. butter
1/2 tsp. dijon mustard
1 tsp. reduced-fat mayonnaise
1 oz. roast beef
Big, hearty slice of pumpernickel bread cut in half
A few whisper thin slices of New York extra-sharp cheddar cheese
Handful of watercress

In a large skillet, melt the butter in the olive oil over moderate heat. Add the onions, turn the heat to low, and cook uncovered for 5 minutes. Then cover and cook for an additional 25-35 minutes, stirring a few times. The onions will turn dark brown and become quite sweet.

In a little teacup, stir together the mustard and mayonnaise. Spread on each half of bread. Top one half with roast beef, just a few onions, watercress, and cheddar. Place the second half on top, and eat with warm tomato soup and ginger gold apple for a thoroughly fall feeling.