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 powder and stir with a whisk to combine. Add to wet mixture and mix just until combined. Spread on a greased baking sheet or parchment lined sheet (use a 13 x 18 pan). Bake at 375 degrees for 12-15 min, until light golden brown or until a toothpick comes out clean (they won't look done so do the toothpick test). Cool completely and frost.
For the frosting:
Combine butter and cream cheese until smooth and creamy. Add vanilla, almond extract, and salt. Add powdered sugar in 1-2 cup increments until combined, then add milk if needed. Spread over cooled cookie bars.