Position 2 racks in the oven, and preheat oven to 175 degrees. Line 2 baking sheets with parchment paper, and set aside. Fill a medium saucepan 1/4 full with water. Set the saucepan over medium heat, and bring water to a simmer.
Combine the egg whites, sugar, and cream of tartar in the heat-proof bowl of an electric mixer, and place it over the simmering water. Whisk constantly until whites are warm to the touch and sugar is dissolved, about 2 minutes. Test by rubbing the mixture between your fingers.
Transfer bowl to mixer stand; fit mixer with the whisk attachment. Starting on low speed and gradually increasing to high, beat egg-white mixture until stiff, glossy peaks form, about 10 minutes. Add vanilla, and mix until combined.
Fit a pastry bag with a #803 Ateco tip, and fill it with the meringue. Pipe teardrop mice shapes onto prepared baking sheets by piping small blobs about 1 inch in diameter, with one pointed end (for the face). Pipe mice about 2 1/2 inches apart. Complete each mouse by inserting a 3-inch-long piece of licorice for the tail, small black candies for eyes and nose, and 2 almond slices for ears.
Bake until mice are hard when gently tapped but still white, about 1 1/2 hours. Do not overbake, or they will crack and begin to brown. Transfer to cooling racks until room temperature.
Store at room temperature in airtight containers up to 1 week.