Food Network teaches how to crush, slice and mince garlic. Peel off some of the papery skin from the garlic and then smash the head of garlic with the heel of your hand to loosen the cloves; if you only need a few cloves, leave the head intact and pull some off. Separate the cloves. To peel a clove, cut away the root end with your knife. Lay the flat side of the knife over the clove while holding the knife handle, then with the heel of your free hand carefully whack the knife against the garlic to separate the skin from the clove. To crush the peeled garlic, lay the flat side of the knife over the clove and smash it again. To slice peeled garlic, lay the clove flat on the cutting board and hold it with the fingertips of one hand, keeping them curled under. Using a rocking motion with the knife, make thin slices by moving the knife slowly across the clove. To mince peeled garlic, lay the flat side of a knife over the clove and smash it. Roughly chop the clove then move your free hand flat across the tip of the knife and use a rocking motion to chop the garlic until it’s finely minced.
For the pea pesto: Pulse together the peas, garlic, Parmesan, 1 teaspoon of salt and 1/4 teaspoon of pepper in a food processor. With the machine running, slowly add the olive oil until well combined, about 1 to 2 minutes. Season with additional salt and pepper, if needed. Transfer to a small bowl and set aside.
For the crostini: Preheat a stovetop griddle or grill pan on medium-high heat. Brush both sides of the sliced bread with olive oil and grill until golden, about 1 to 2 minutes. Transfer the bread to a clean surface and spread 1 to 2 tablespoons of the prepared pesto on each slice.
Top with tomato halves and serve.
*Cook's note: If you don't have day-old bread on hand, you can dry out fresh bread by putting the slices in a preheated 300 degree F oven until slightly crisp, about 5 minutes.