Prepare the lava center by heating heavy cream until simmering, then pouring over chopped chocolate. Stir until smooth and refrigerate for 30 minutes until firm.

Scoop the chilled ganache into 12 small balls and place them in the freezer for at least 20 minutes until solid.

In a large bowl, cream together softened butter, granulated sugar, and brown sugar until light and fluffy.

Beat in the egg and vanilla extract into the creamed mixture.

In a separate bowl, whisk together flour, cocoa powder, baking soda, and salt.

Gradually incorporate the dry ingredients into the wet ingredients until a uniform dough forms.

Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius) and line a baking sheet with parchment paper.

Divide the cookie dough into 12 equal portions. Flatten each portion, place a frozen ganache ball in the center, and wrap the dough around it, ensuring it is completely sealed.

Arrange cookies on the baking sheet and bake for 10 to 12 minutes until the edges are set but the centers remain soft.

Allow cookies to rest on the baking sheet for 5 minutes before serving warm to ensure a liquid center.