Set a marble plate, a Pyrex plate or a large plate in the freezer.
In a bain-marie, slowly melt dark chocolate.
Meanwhile, hull strawberries while being careful to remove strawberry's heart (the white part that looks like a carrot). Also slice tips. It will help you make it stand.
Place the refrigerated plate near the plate with melted chocolate. It's also possible to set a a parchment paper over. It will ease to take off strawberries once finished.
With a fork, verticaly sting strawberries to be able to soak into chocolate. Lay everything, make it stand on the plate. Chocolate will freeze and act as a foot to maintain strawberry standing.
With a pastry syringe or a small spoon, pour some drop of Porto into each strawberries. Do not fill them up too much. Then, set in the refrigerator for an hour.
Melt white chocolate.
Take out strawberries of the refrigerator and pour melted white chocolate, over each strawberries with a small spoon to cover Porto inside the strawberry. Set again in refrigerator until serving.
Take off carefully strawberries base with a knife then serve.
Chef’s note
It's possible to replace white chocolate with milk chocolate.