With their savory, aromatic fillings and a flavor-charred crunch, these melty, satisfying sandwiches are grilled cheese for grown-ups. A heavy skillet does the work of a panini press.
In nonstick 12-inch skillet, heat oil over medium heat.
Stir in onions and salt and pepper; cover and cook 15 minutes or until very soft, stirring occasionally.
Uncover and cook 15 to 25 minutes longer or until onions are golden brown, stirring frequently.
Stir in thyme; remove pan from heat.
Prepare outdoor grill for direct grilling over medium heat.
Meanwhile, assemble panini: Place 4 slices bread on work surface.
Spread one-fourth of goat cheese on each slice and top with one-fourth of onion mixture.
Top with remaining bread slices.
Place 2 panini on hot grill grate.
Place heavy skillet (preferably cast iron) on top of panini, press down, and cook 7 to 8 minutes or until bread is toasted and browned on both sides, turning over once.