Instructions
Heat air fryer to 370°F.
Bring 1 inch of water to a simmer in a medium saucepan.
Combine chocolate chips and butter in a large heatproof bowl and place the bowl over simmering water to gently melt, stirring occasionally, until smooth.
Remove the bowl from heat and let it cool slightly.
In a medium bowl, whisk together granulated sugar, eggs, yolks, vanilla, and salt until well combined.
In a small bowl, whisk together flour, cocoa powder, and baking powder.
Add the egg mixture to the chocolate mixture and whisk until combined; add the flour mixture and gently whisk until the batter is smooth.
Divide half of the batter among six prepared 6-ounce ramekins.
In a second small bowl, stir together peanut butter and confectioners’ sugar until combined.
Scoop 1 tablespoon of the peanut butter mixture into each half-filled ramekin.
Cover with the remaining chocolate batter, dividing it among the ramekins.
Place ramekins in the air-fryer basket and air-fry until cakes have puffed and are set, about 8 minutes.
Carefully remove the ramekins and let them rest for 2 minutes.
Loosen the edges of the cakes and carefully invert them onto plates to serve.
Pro Tips
Working in batches is highly recommended for even cooking.
Ensure the bowl of chocolate and butter is placed over, not in, the simmering water to prevent overheating.
Let the chocolate mixture cool slightly before adding the eggs to avoid scrambling them.
Dusting the ramekins with sugar helps the cakes release easily after baking.