Combine the sugar, water, and dried lavender in a small saucepan over medium heat. Stir until the sugar is completely dissolved and the mixture just reaches a simmer.

Remove from heat, cover, and allow the lavender to steep for 30 minutes. Strain out the lavender buds through a fine mesh strainer and let the syrup cool completely before using. It keeps in a sealed jar in the fridge for up to two weeks.

Steep 2 earl grey tea bags in 1 cup of just-boiled water for 5 minutes exactly. Remove the bags — don’t squeeze them — and let the tea cool to room temperature, then refrigerate until fully cold.

Fill two glasses generously with ice. Divide the chilled earl grey tea between the glasses, then add 1 tablespoon of lavender syrup and half the lemon juice to each.

Stir gently to combine, then top each glass slowly with sparkling water or tonic. Stir once more, just lightly, to bring everything together without losing the bubbles.

Garnish with a lavender sprig and a lemon wheel on the rim and serve immediately.