Preheat oven to 350 degrees F (175 degrees C). Spray 20 muffin cups with cooking spray and dust with flour, or line with paper liners.
Melt chopped dark chocolate in a microwave-safe glass or ceramic bowl in 15-second intervals, stirring after each melting, 1 to 3 minutes.
Beat eggs in a large bowl with an electric mixer until light and fluffy; beat in sugar gradually on high speed. Add cream and beat until batter has doubled in volume. Beat in butter until well combined. Beat in flour and salt on low speed until well combined. Beat in melted chocolate on medium speed until well combined. Stir in chocolate chips and pecans. Pour batter into muffin cups.
Bake in preheated oven until tops spring back when lightly pressed, 20 to 25 minutes.
