In a small bowl, whisk together butter, garlic, Italian seasoning and lemon juice; season with salt and pepper, to taste. Brush zucchini slices with butter mixture.
Heat a grill pan over medium high heat. Add zucchini in a single layer and grill until charred on both sides and just beginning to soften, about 2 minutes per side.
Serve immediately, garnished with parsley, if desired.