Preparation

• Position oven racks in the top and bottom thirds of the oven and heat the oven to 350°F. Line 2 large rimmed baking sheets with parchment.
• Combine the condensed milk, tahini, and vanilla in a large bowl. Add the coconut and stir with a large silicone spatula until thoroughly mixed.
• Beat the egg whites and 1/4 tsp. of the salt with an electric mixer on medium speed until stiff peaks form, about 4 minutes. Using the spatula, fold the whites into the coconut mixture. Push the mixture together into a mound.
• With wet hands or two wet spoons, gently form rounded tablespoonfuls of batter into balls about 1-1/2 inches in diameter. Arrange 2 inches apart on the baking sheets.
• Bake, rotating and swapping the positions of the pans halfway through, until the macaroons are golden brown in spots and their undersides are tanned, about 25 minutes.
• Cool briefly on the baking sheets on racks, then transfer the macaroons directly to the racks to cool completely.
• Heat the sugar in a small heavy-based saucepan over medium-low heat. When mostly melted, stir it and cook until fully melted and amber. Stir in the butter, sesame seeds, and the remaining 1/4 tsp. salt. Using a metal spoon, drizzle over the baked macaroons and let cool.

Make Ahead Tips

The macaroons will keep, uncovered at room temperature, for up to 3 days, or refrigerated in an airtight container for up to 3 weeks. They can also be frozen for up to 6 months.