1-First Step: Make the basil pesto Add the basil leaves, pine nuts, grated Parmigiano cheese, and minced garlic to a food processor. Pulse a few times until the mixture looks finely chopped. Then slowly pour in the olive oil while blending until the pesto becomes smooth but still a little textured. Taste it and add salt and pepper as needed. If you want a lighter flavor, use a little less garlic. For a stronger pesto, add one extra clove.

2-Second Step: Prep the vegetables and bread Slice the tomatoes into 1/4-inch thick rounds and lay them on a plate. Sprinkle lightly with flaky sea salt or kosher salt, then let them sit for a minute or two. This helps pull out a little moisture and improves the flavor. At the same time, slice the bread into 8 equal pieces if it is not already cut. If you are using a gluten-free loaf, toast it a bit first so it can stand up to the fillings.

3-Third Step: Toast or grill the bread Brush the outer sides of the bread lightly with extra-virgin olive oil. If you are making a caprese panini, preheat a skillet, grill pan, or panini press to medium heat, about 350°F. Toast the bread until it is golden and crisp on the outside, about 2 to 4 minutes per side in a skillet or 3 to 5 minutes in a panini press. A crisp surface helps keep the sandwich from turning soggy, which is especially useful if you are packing lunch for later.

4-Fourth Step: Build the layers Spread basil pesto on the inside of each bread slice. Use enough to coat the surface, but not so much that it drips out. Add a layer of baby arugula, then mozzarella slices, then tomato rounds. If you like, add another small spoonful of pesto on top of the cheese for extra flavor. Finish with a light drizzle of thick balsamic vinegar or glaze if using. The balsamic adds a sweet-tart note that works beautifully with the creamy cheese and juicy tomatoes.

5-Fifth Step: Assemble the caprese sandwich with basil pesto Close the sandwich with the second bread slice, pressing down gently. If you are making open-faced sandwiches, keep the top off and serve the layers on one slice of bread. For a grilled caprese sandwich with basil pesto, return the assembled sandwich to the skillet or press for 1 to 2 more minutes, just until the mozzarella begins to soften. Keep the heat at medium so the bread does not burn before the cheese warms through.

6-Final Step: Slice and serve Let the sandwich rest for 1 minute before cutting. This helps the cheese settle and keeps the layers from sliding apart. Slice diagonally for a classic café-style look, then serve right away. You can pair it with a simple side salad, soup, or chips if you want a fuller meal. For a lighter lunch, serve it with extra arugula on the side and skip the balsamic glaze.