Heat ¾ cup sugar and the water in a large saucepan over medium heat. Bring to a boil and let cook 10 to 12 minutes or until beginning to turn golden; swirl pan and continue to cook until deep amber.

Add 1 cup whipping cream (mixture will sputteand stir until caramel is dissolved; remove from heat. Stir in salt and vanilla paste; let cool to room temperature.

In a large heatproof bowl, whisk egg yolks with remaining ¼ cup sugar.

In a clean medium pot, heat remaining 1 cup cream and the milk over medium heat until steaming; slowly whisk in half of milk mixture into egg mixture. Add egg mixture to remaining milk mixture in pot and cook, stirring constantly, until thickened (do not let mixture boil). Strain egg and milk mixture through a fine-mesh sieve into a heatproof bowl. Whisk in caramel mixture, then tahini; chill for 2 to 3 hours, stirring mixture occasionally.

Prepare in ice cream maker according to manufacturer’s instructions. Scrape into an airtight container and freeze until firm.