melt butter and chocolate
Preheat your oven to 190 C / 375 F. Add butter and chocolate into a jar (or bowl) with a pinch of salt. Place the bowl over a pot of simmering water (make sure the bottom of the bowl is not touching the water) and let both butter and chocolate melt completely, then remove from the heat and let cool to room temperature. If you want, you can melt the mixture in a microwave as well.
prepare the batter
Crack eggs into a separate, clean bowl, add sugar and mix with a hand mixer until triple the size and pale yellow, for about 5 minutes. Gradually add melted chocolate mixture (at room temperature) while mixing constantly. Sift the flour into the mixture and mix to combine. Make sure the batter is nice and without lumps.
fill the cups or rings
Grease your custard cups or pastry rings (approx. 8 cm / 3-inch in diameter) with butter. If you are using pastry rings make sure to place them onto a baking sheet lined with parchment paper before filling them with batter. Fill your custard cups or pastry rings for up to two thirds. First fill about a third of the cup (or pastry ring), then add the white chocolate drops and the rest of the chocolate lava batter until you fill the cups (or pastry rings) to about 2/3.
Place in the oven, on middle rack and bake for about 10 - 11 minutes at 190 C / 375 F.
Serve immediately. Carefully remove the custard cups and pastry rings. Dust each chocolate molten lava cake with unsweetened cacao, add a pinch of salt and serve. Enjoy