In a medium-sized bowl, whisk together the flour and cocoa powder. In a separate bowl, cream together butter, sugar, salt, baking soda, vanilla, and coconut extract until fluffy and light, at least 3 to 4 minutes. Add eggs, one at a time, beating until each is incorporated, scraping down the bowl as needed. With the mixer on low speed, add dry ingredients in three batches, alternating with milk, until just combined.