Steps
1. Start by heating a skillet over medium heat.
2. Cook the sausage link in the skillet until browned and cooked through, about 5-7 minutes. Remove and slice it lengthwise.
3. In the same skillet, melt the butter and toast the bread slices until golden brown on both sides.
4. Once the bread is toasted, place one slice in the skillet, add the sliced sausage, and top with cheddar cheese.
5. Cover the sandwich with the second slice of bread and cook for another 2-3 minutes, flipping once, until the cheese melts.
6. Remove from heat, spread mustard on the inside if desired, and add fresh arugula for a peppery crunch.
7. Cut in half and serve hot!