8 slices Provolone cheese, each cut in half (Mozzarella could also be used)
1/4 cup very thinly sliced red onion
1 small can (2.25 oz) sliced black olives, drained (Kalamata would also be great!)
6 oz roasted red peppers in olive oil, drained and sliced into smaller pieces if too large (Mine were mini red peppers and I sliced them into 2–3 pieces each)
3 Tbsp crumbled feta cheese
1 large handful baby spinach, chopped
4 Tbsp butter, melted
2 Tbsp olive oil
1/2 tsp garlic powder
Place a long sheet of wax paper on the counter, then lay all 16 half-slices of sourdough on the wax paper, with top and bottom slices lying open and facing one another as you build each sandwich.
Spread 1/2 Tbsp pesto onto each half-slice.
Place a half-slice of Provolone on top of the pesto on each half-slice of sourdough. You’ll continue to build the sandwich on top of the Provolone on one side of the sandwich.
Layer the red onions, black olives, feta, roasted red peppers, and spinach onto one side of each sandwich.
Flip the other half-slice of each sandwich with pesto and Provolone over on top of the slice holding all the toppings. You should now have 8 assembled sandwiches lined up on the wax paper.
Now melt the butter and whisk in the olive oil and garlic powder. Use a pastry brush to coat the top slice of all 8 sandwiches with the garlic-butter-oil blend.
Use the remaining garlic-butter-oil blend to brush the griddle/pan generously. (I use either my cast iron griddle or a heavy duty stainless pan)
Heat the griddle/pan over medium heat until garlic-butter-oil just begins to sizzle. Be sure the garlic-butter-oil is spread around enough to cover the bottom of each sandwich (If you’re cooking in batches, be sure to reserve enough of the garlic-butter-oil for remaining sandwiches).
Use a spatula to transfer the sandwiches, dry side down, to the hot griddle/pan. Turn the heat down to low-medium.
My trick for getting the cheese to melt without burning the edges of the sandwich is to allow both sides of the sandwich to reach your desired level of crispy golden brown, then turn the heat down to low (or turn the burner off entirely) and cover it loosely with a foil “tent” for a few more minutes.
If cooking in batches, place cooked sandwiches on a large plate covered loosely with foil to keep them warm until ready to serve.