Put the dark chocolate and sweetened condensed milk in a large microwave safe bowl. Microwave at 50% power for 1 minute, then remove and stir. Microwave in additional 30-second intervals until chocolate is almost completely melted (2 minutes total was perfect for me). Stir until smooth. Mixture will be thick and sticky, do not overheat. Stir in sliced almonds.

Spread evenly into the bottom of the prepared pan. Set aside.

Pour the sweetened condensed milk into a large bowl. Add vanilla and powdered sugar and mix until smooth. It will be very dry at first, but will come together after a minute or so.

Add 2 cups of the flaked coconut and stir until combined. If mixture still appears quite runny, add the remaining 1/2 cup of flaked coconut.

Spread evenly on top of the fudge layer. Chill for at least 20 minutes.

In a microwave safe bowl, melt the dark chocolate on 50% power for 1-2 minutes until smooth. Spread evenly on top of the coconut layer.

Top with whole almonds. If desired, use a knife to "score" the melted chocolate into 36 pieces before adding the almonds. This helps with placement.

Chill for at least 2 hours. Remove fudge from pan and peel away foil. Cut into pieces and serve or chill for later. Fudge will keep in the fridge for up to 1 week.