Place the rooibos in a heatproof pitcher and cover with the boiling water. Cover and steep 5 minutes. Strain through a small mesh strainer, stir in the sugar to dissolve, and let cool. Place the tea in a blender with the vanilla bean seeds, peaches, and lemon juice and puree smooth. Strain the puree, pressing on the solids to extract all the good stuff. You should have about 2 cups of puree. Gently pour in the sparkling water and stir to combine; it will bubble up a lot. The soda is best fresh as the peaches oxidize quickly.
To make floats, divide the ice cream among 4 large glasses and gently top with the peach soda, adding a splash more sparkling water to make them foam up. Serve immediately.
In place of the vanilla bean, feel free to use vanilla rooibos or ½ teaspoon vanilla paste or extract.Sarah's Vegan Vanilla Bean Ice Cream is on point and easy to make, but feel free to replace it with your favorite vanilla ice cream if need be.Nutritional values are based on one of four servings.