Using a double boiler on your propane stove, add dark chocolate morsels, and over low heat allow the chocolate to melt. Gently stir to ensure fully melted and avoid burning. When smooth and melted, set aside and allow it to cool to room temperature.
In a separate bowl, whip the heavy whipping cream until stiff peaks form.
Using a large mixing bowl or standing mixer, combine softened butter and granulated sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition. Continue to mix until the mixture becomes smooth and silky.
Stir in the vanilla extract, followed by the cooled melted dark chocolate. Mix until well combined.
Gently fold the whipped cream into the chocolate mixture until well combined.