Place 1 1/4 cup spinach leaves on parchment paper large enough to seal tightly.
Place each fillet on spinach leaves.
On each fillet, before sealing, place a bay leaf, a 3 lemon slice halves, a pat of butter, 4 asparagus spears or green beans, 1/4 cup diced tomatoes, and 1/8 cup olives, Garnish with capers to taste. Fold snugly in parchment and staple shut. This can be done in advance and refrigerated until ready to cook. Bake at 425 F for 15 to 25 minutes and serve immediately. When it is getting close to done, the top of the parchment paper starts to turn brown. Parchment paper can be found in most in-store bakeries and kitchen supply stores. (You can also find a rather large roll at Costco.).