Preheat oven to 350°F. Line muffin tin with paper muffin cups. (No need to grease the tin or cups before filling.)

Sift together flour, baking soda, and salt onto a plate or large piece of parchment.

Beat together eggs, sugar, yogurt and vanilla with an electric mixer at high speed mixture is thick and turns pale, 6-7 minutes. Reduce speed to low and slowly pour in oil. Add bananas and mix until fully incorporated. Fold flour mixture in by hand.

Heat cream in a small pan over medium-high heat until just begins to boil, stirring to prevent burning. Remove from heat and whisk in dark chocolate until mixture is smooth and even.

Spoon banana batter into each muffin cup to fill to roughly half full. Dollop 1 tsp. of chocolate in the middle of each cup. Top with another layer of batter (just enough to fully conceal the chocolate), leaving about 1/2 inch of space between the top of batter and the top of the muffin cups. (Alternatively, fill the cups with batter and use a pastry bag filled with the chocolate mixture to inject the center of the batter with chocolate.)

Bake until tops of cupcakes are golden brown and a tester inserted into the middle comes out free of banana bread (it certainly may contain some of the gooey chocolate though), about 30 minutes. Cool on a wire rack.

For the frosting: When cupcakes have cooled completely, beat together the butter and cream cheese until smooth. Gradually add the powdered sugar, beating well after each addition, until the mixture is smooth and stiff. Top each cupcake with a healthy does of frosting.