Salted Dark Chocolate Truffle Cookies

unsalted butter 4 oz bittersweet chocolate, chopped 2 cups dark chocolate chips 1/2 cup + 2 Tbsp flour 2 Tbsp dark chocolate/dutch process cocoa powder 1/4 tsp salt 1/4 tsp baking powder 3 eggs 3/4 cup sugar 2 tsp vanilla coarse sea salt for sprinkling