Cream butter and sugar until fluffy. Add eggs, one at a time, mixing after each egg. Add vanilla and almond extract, and mix well. In a separate bowl combine flour, salt, baking soda, cream of tartar, and stir with a whisk to combine. Add to butter mixture and mix just until combined. Spread onto a greased jellyroll pan. Bake at 375 degrees for 10-15 min, until light golden brown or until a toothpick comes out clean. Cool completely and frost, if desired.
For frosting: combine butter and cream cheese until smooth and creamy. Add vanilla, almond extract and salt. Add powdered sugar 1 to 2 cups at a time until well combined, then add milk a little at a time and mix until smooth and free of lumps. You may not need all the milk, just mix in enough to reach the desired consistency. Mix in food coloring if desired and mix well. Spread over cooled cookie bars.