In a small sauce pot, combine sugar and water. Set over medium-high heat and cook to 238°F.
Meanwhile, the bowl of a stand mixer fitted with a whisk attachment, beat egg whites and cream of tartar on low speed. Once mixture is foamy, increase speed slightly and whisk to soft peaks. By this time, the sugar syrup should have reached its desired temperature. With the mixer running on medium speed, slowly pour in the hot sugar syrup.
Once all the sugar syrup as been added, increase speed and beat until shiny, stiff peaks. Add vanilla and salt and whisk until incorporated.
Spoon meringue over milk soaked cake. Use the back of the spoon to evenly distribute meringue. Use a kitchen torch to brown and toast the meringue. Slice and serve immediately.