Combine 2 crushed garlic cloves with about 3 tablespoons of olive oil, then brush approximately half of this garlic-infused oil onto each bread slice. Place the baking sheets in the oven and bake for 10 minutes.

Once the time is up, remove the sheets, flip each slice over, brush with the remaining garlic oil, and return to the oven for another 10 minutes until the crostini are crisp and golden brown. Allow the toasted bread to cool completely before adding toppings.

While the bread toasts, prepare the sun-dried tomato spread. Pat 4 sun-dried tomatoes in oil dry with a paper towel and cut them into small pieces.

Transfer the tomato pieces to a food processor along with 2 tablespoons of butter and process until finely chopped. Alternatively, you can use a mortar and pestle to pound the mixture to your desired consistency.

Season the paste with salt and black pepper to taste, adjusting until the flavors are balanced and satisfy your palate.

To finish the crostini, spread the sun-dried tomato and butter mixture generously over each cooled slice of bread. Top with the chopped 12 pitted black olives, distributing them evenly across each piece.

Finally, sprinkle ¼ teaspoon of fresh chopped rosemary over the olives as a fragrant finishing touch. Serve immediately for the best texture and flavor.