Preheat the oven to 375 F. Spread both sides of the bread with pesto, close, and cut crosswise into 2-inch sections, making sure not to cut all the way through to keep the bread together. Wrap in foil, leaving the bread slighty exposed, and bake until crusty and hot, 20-25 minutes.
*To grill the bread, place the foil-wrapped bread, slightly open side up, on a medium-hot grill and grill until toasty and hot, 10 minutes.