Follow these detailed instructions carefully to ensure your crostini are perfectly crisp, flavorful, and assembled for maximum enjoyment. The key is in the technique and the timing.

Part 1: Preparing the Crostini Base

1. Preheat Your Oven: Begin by preheating your oven to 375°F (190°C). Position a rack in the middle of the oven to ensure even cooking and browning.
2. Slice the Baguette: Using a sharp, serrated bread knife, slice the baguette on a slight diagonal (a bias cut). This creates more surface area for the topping and makes for a more elegant presentation. Aim for slices that are about 1/2-inch thick. Slices that are too thin may burn or break, while slices that are too thick can be difficult to bite into. You should get between 20-24 slices from a standard baguette.
3. Oil and Toast the Bread: Arrange the baguette slices in a single, even layer on a large baking sheet. Do not overcrowd the pan; use two if necessary. Using a pastry brush, lightly brush both sides of each slice with about half of the extra virgin olive oil. Toast in the preheated oven for 10-15 minutes, flipping the slices halfway through. You are looking for a beautiful, pale golden-brown color and a crisp, dry texture. The center should be completely toasted, not soft. This step is crucial for creating a barrier against the moisture of the tomato topping.
4. Infuse with Garlic: Once the toasts are out of the oven and still warm, take one whole, peeled garlic clove and gently rub its cut surface over one side of each toast. The heat and rough texture of the toast will act like a grater, releasing the garlic’s essential oils and imparting a wonderful, subtle garlic aroma and flavor without being overpowering. Set the toasts aside to cool completely.

Part 2: Crafting the Tomato Basil Topping

1. Prepare the Tomatoes: Wash and dry the Roma tomatoes. Cut them in half lengthwise and use a small spoon or your fingers to gently scoop out the seeds and excess watery pulp. This is the most important step in preventing a soggy topping. Once deseeded, finely dice the tomatoes into small, uniform pieces (about 1/4-inch). Place the diced tomatoes in a medium-sized mixing bowl.
2. Prepare the Aromatics: Finely mince the remaining garlic clove. For the basil, stack the leaves on top of each other, roll them tightly into a small cigar shape, and then thinly slice them crosswise to create a beautiful chiffonade. Add the minced garlic and sliced basil to the bowl with the tomatoes.
3. Combine and Season: Drizzle the remaining extra virgin olive oil over the tomato mixture. Season generously with sea salt and freshly ground black pepper. Gently stir everything together until just combined. Be careful not to overmix, as this can make the tomatoes release too much water.
4. Let the Flavors Marry: Allow the tomato mixture to sit at room temperature for at least 15-20 minutes before serving. This brief resting period allows the salt to draw out the tomatoes’ flavor and for the garlic, basil, and olive oil to meld together into a cohesive, delicious topping.

Part 3: Assembling and Serving

1. Assemble Just Before Serving: This final step should be done right before you plan to serve the crostini to ensure they remain as crisp as possible. Using a spoon, place a generous portion of the tomato-basil mixture onto the garlic-rubbed side of each cooled toast.
2. The Final Flourish: Arrange the assembled crostini on a platter or wooden board. Just before presenting them, drizzle the balsamic glaze over the top of each one in a zigzag pattern.
3. Serve Immediately: Serve your beautiful and delicious Tomato Basil Crostini right away and enjoy the burst of fresh, vibrant flavors.