Preheat your oven to 450°F (conventional) and prepare two 6 oz ramekins by generously brushing butter inside.
Combine chocolate and butter in a heat-safe bowl, then microwave in 20-second increments until melted. Stir to blend.
In a separate bowl, use an electric hand mixer to whisk together the egg, sugar, salt, and vanilla for 2-3 minutes until the mixture becomes light, frothy, and nearly triples in volume.
Pour the melted chocolate mixture into the egg mixture and whisk until just combined.
Sift in the flour and gently fold it in using a rubber spatula. Be careful not to overmix.
Add the red food color and gently fold again, adjusting the quantity based on your desired color intensity.
Divide the batter between the two ramekins and bake for approximately 10-11 minutes until the edges are set but the center remains molten, as indicated by a slight wobble.
Allow the cakes to cool in the ramekins for 1-2 minutes, then carefully turn them out onto dessert plates. Dust with powdered sugar, and voila – your delightful treat is ready to be savored!