1. Lay out your sourdough bread slices on a clean surface. Generously butter one side of each slice. You want an even layer of butter from edge to edge to ensure consistent browning and crispiness.

2. Place four slices of bread, butter-side down, into a large skillet or griddle set over medium-low heat. Immediately top each of these bread slices with two slices of Havarti cheese. The heat will start to gently warm the cheese.

3. On top of the Havarti cheese, layer several thin slices of fresh tomato. Arrange them evenly so each bite gets some tomato. Then, scatter a generous amount of fresh basil leaves over the tomatoes.

4. Place two more slices of Havarti cheese on top of the basil and tomato layers. This acts as a “glue” to hold the sandwich together and adds extra creaminess. Finish by placing the remaining four slices of sourdough bread, butter-side up, on top of the assembled sandwiches.

5. Cook the sandwiches for about 5-7 minutes on the first side. You’ll know it’s time to flip when the bottom slice is deeply golden brown and the cheese has started to melt around the edges. Use a wide spatula to carefully flip each sandwich.

6. Continue cooking for another 5-7 minutes on the second side, or until that side is also golden brown and crispy, and all the cheese inside is fully melted and gooey. The bread should be firm and toasted, not soft.

7. Once cooked, remove the grilled cheese sandwiches from the skillet and place them on a cutting board. Let them rest for a minute or two before slicing diagonally. This brief rest helps the cheese set slightly, preventing it from oozing out too much when cut. Serve immediately.