Step 1In a small bowl, whisk together the cinnamon and sugar. Set aside.
Step 1In a heavy-bottom saucepan, combine the brown sugar, heavy cream and salt over medium-low heat. Cook, stirring with a heat-proof spatula until the brown sugar is fully dissolved. Stir in the butter until it is melted and the mixture comes to a slow boil. Cook the caramel for 5 to 7 minutes, stirring frequently, then remove from heat and stir in the vanilla. Set the mixture aside until ready to drizzle over the cookies. Rewarm the caramel before drizzling. For thicker caramel, whisk in a little cornstarch slurry while the mixture is warm.
Step 1In a large bowl, whisk together the flour, cream of tartar, baking soda and salt.
Step 2In a separate mixing bowl, beat together the butter and sugar until light and fluffy, 3 to 5 minutes. Beat in the eggs, 1 at a time, until fully incorporated. Slowly beat the dry ingredients into the batter to form the dough.
Step 3Cover and refrigerate the dough until well-chilled, at least 2 to 3 hours and preferably overnight (the dough must be well-chilled or the caramels will sink to the bottom of each cookie and burn). Meanwhile remove the wrappings from the caramel squares. Cut each one in half so the squares are long and thin.
Step 4Heat the oven to 350 degrees.
Step 5Form the cookies: Roll about 1½ tablespoons chilled dough into a ball and bury a caramel square so the candy is closer to the top of the ball than the bottom (this is so the caramel does not seep through the bottom of the cookies as they bake). Roll the balls in the cinnamon sugar mixture and place the cookies about 3 inches apart on parchment-lined baking sheets.
Step 6Bake the cookies until set and the edges are golden-brown, 12 to 14 minutes. Remove and cool the cookies.
Step 7Drizzle the warm caramel sauce over the cookies and sprinkle over sea salt to garnish.