Grease 12 small forms and sprinkle them with crushed nuts. Melt the butter and couverture chocolate in a water bath. Separately, beat the egg yolks, powdered sugar, rum and chili.
Pour the chocolate mixture to the egg mixture slowly, while continuously stirring, then add the flour. When everything is homogenized, dispense it into the forms, up to 1/2″ (1 cm) below the rim.
Put them to bake for 8 minutes in a preheated 356°F (180 °C) oven. Serve the chocolate gateau warm and inverted onto a plate.