01 -
Heat a large skillet over medium heat. Brown the ground beef, breaking it up with a spatula, until fully cooked, about 5 to 7 minutes. Drain excess fat.
02 -
Reduce heat to low, add 1 cup marinara sauce to the beef, and simmer for 2 to 3 minutes until heated through. Remove from heat and set aside.
03 -
In a medium bowl, combine ricotta cheese, grated Parmesan, and Italian seasoning. Stir until smooth and well blended.
04 -
Spread 0.5 tablespoon softened butter on one side of each slice of sourdough bread evenly.
05 -
On the unbuttered side of four bread slices, spread about 2 tablespoons of ricotta mixture. Evenly spoon one-third cup of the beef mixture over it, then top with 0.25 cup shredded mozzarella. Repeat with remaining slices.
06 -
Cover each assembled slice with a remaining slice of bread, buttered side facing up.
07 -
Heat the large skillet over medium heat. Place one or two sandwiches at a time in the skillet. Cook each side for 3 to 4 minutes until bread is golden brown and cheese melts thoroughly.
08 -
Serve immediately with the remaining marinara sauce on the side for dipping.