Combine all of the ingredients together and stir until well blended.
Take four 15-inch squares of parchment paper and fold each one in half. Trace the outline of half a heart on each piece of paper so that when you cut them out and unfold the paper you will have whole heart-shaped pieces. They should be about 15 inches across. Place a salmon fillet on the left side of each piece of paper (right side if you're left-handed). Place a spoon of basil butter on each fillet and top with 2 slices of tomato. Add lemon slice, bay leaf, salt and pepper. Fold right side of parchment paper over the salmon and starting at the top of the folded heart, make one-inch folds all along the edge of the packet until it's completely sealed.
Preheat the oven to 325 degrees. Put the four packets on a baking sheet. Bake for 25 to 30 minutes. Remove from oven. Place each packet on a dinner plate and slice open the top with knife or scissors. Smell the aroma! It's wonderful.