Preheat oven to 425 degrees with the oven rack in the middle. Rub two 6-oz glass Pyrex baking cups (linked to the ones I use in Notes) with coconut oil. Set aside.
In a small glass mixing bowl, combine the chocolate chips and coconut oil. Microwave for 1 minute, and let stand.
While the chocolate chips and coconut oil are standing, in a small mixing bowl add the egg, egg yolk, sugar and salt. Beat with a fork until combined.
Stir to combine the melted coconut oil and chocolate chips.
While stirring the egg mixture, slowly pour in the melted chocolate mixture. Stir until combined.
Add the flour. Stir to combine.
Divide the mixture between the 2 cups, and put on a baking sheet. Bake for 13-14 minutes, until the cakes have puffed up and the outsides are set.
Take out of the oven, and let the cakes sit in the cup for no longer than a minute (otherwise they'll keep baking). Transfer the cakes to a plate. Serve right away while still warm with coconut whipped cream and berries.