Preheat the oven to 350 degrees F. Halve the baguette lengthwise and then crosswise to make 4 large pieces.
Put a wire rack on a baking sheet. In a small bowl, mix the butter, garlic, parsley and salt, if using, until fully combined. Spread the mixture evenly over the cut sides of the baguette. Put the baguette pieces cut-side up on the wire rack and bake until golden brown and crunchy, 5 to 7 minutes. Serve hot.