Notes: You can toast the bread (step 1) up to 4 hours ahead; cool and store airtight at room temperature.
Cut baguette diagonally into 1/3-inch-thick slices. Set slices on a rack on a 14- by 17-inch baking sheet. Bake in a 425° regular or convection oven until golden, 6 to 8 minutes.
Drain mozzarella and pat dry; cut into 1/4-inch-thick slices. Arrange on toast, cutting slices to fit. Drizzle olive oil over cheese. Sprinkle with herbs and salt and pepper to taste.