To small saucepan, add 4 sprigs of thyme and honey and cover with boiling water. Simmer on medium heat for 5 minutes. Turn off heat and allow to cool for a further 5 minutes. Remove thyme sprigs.
To large jug, add raspberries and muddle with wooden spoon. Pour honey mixture and lemon juice into jug and stir to combine. Chill for several hours until very cold.
When ready to serve, add sparkling water or soda and serve over ice. Garnish with lemon slices and additional sprigs of thyme.