Answer:
Cinnamon
Explanation:
From the given ingredient the recipe is meant for cinnamon-sugar cookies
Given the list
(Cinnamon, Baking Soda, Pure Vanilla Extract, Salt ,Cream of Tartar)
With me here is a typical recipe for the baking of cinnamon-sugar cookies
1 cup C&H® Golden Brown Sugar
½ cup C&H® Granulated Sugar
½ cup (1 stick) Unsalted butter, softened
1 teaspoon Pure vanilla extract
2 large eggs
2 ½ cups All-purpose flour
1 teaspoon Cream of tartar
½ teaspoon Baking soda
¼ teaspoon salt
2 tablespoons Granulated Sugar
2 teaspoons ground cinnamon
Now 6- 1/4tsp. corresponds to 6(0.25)=1.5tsp
1.5tsp is a close approximation of 2 teaspoons Ground cinnamon in our typical recipe, hence we could predict that Thea added Cinnamon last