Bring 4 cups of water to a rolling boil. Position the Earl Grey tea bags and a slice of lemon in a quart-sized jar, then carefully pour the hot water over them. Cover the jar and allow the tea to steep undisturbed at room temperature for 2 hours. Incorporate the raw honey, stirring thoroughly, then place the jar in the refrigerator to chill for a minimum of 2 additional hours. Prior to serving, discard the tea bags and lemon slice, then dilute with 2 to 3 cups of water, adjusting the strength to your preference. If desired, stir in a splash of pure vanilla extract. Serve over ice and embellish each glass with fresh lemon slices.