1. Prepare the Bread and Butter: Take your softened butter and spread a thin, even layer on one side of each sourdough bread slice. This buttered side will be the exterior of your sandwich, ensuring a beautiful golden-brown crust.

2. Assemble the First Layer: Place two slices of sourdough bread, buttered-side down, onto a clean work surface or cutting board. Lay two slices of your chosen cheese on top of each of these bread slices.

3. Add the Fresh Tomatoes: Arrange two slices of ripe summer tomato over the cheese on each sandwich. Season the tomatoes lightly with a pinch of salt and a pinch of black pepper to enhance their flavor.

4. Complete the Sandwich: Place the remaining two slices of sourdough bread on top of the tomatoes, with the buttered side facing up. You should now have two fully assembled sandwiches, buttered on both exterior sides.

5. Heat the Skillet: Place a large non-stick skillet or griddle over medium heat. Allow it to heat up for about 2-3 minutes. You want it warm enough to sizzle the butter but not so hot that it burns the bread quickly.

6. Grill the First Side: Carefully place the assembled sandwiches into the hot skillet. Cook for 4-6 minutes, or until the bottom slice of bread is golden brown and the cheese has started to melt. You should see the cheese softening and beginning to ooze.

7. Flip and Finish Grilling: Using a spatula, carefully flip each sandwich to the other side. Continue to cook for another 4-6 minutes, or until the second side is golden brown and the cheese is fully melted and gloriously gooey. You might need to gently press down on the sandwiches with your spatula to ensure even browning and good contact with the pan.

8. Serve Immediately: Remove the grilled cheese sandwiches from the skillet. For the best experience, slice them in half diagonally and serve them right away while the cheese is still warm and stretchy.