First Step: Prep Oven and Ramekins
Preheat your oven to 425°F (218°C). For convection ovens, 350°F (180°C) works, adjusting baking times accordingly. Grease four 6-ounce ramekins well with nonstick spray or butter, then dust them with cocoa powder. This step prevents sticking and adds subtle flavor.

Second Step: Melt Chocolate and Butter
Coarsely chop 6-7 ounces of semi-sweet or dark chocolate. Place it with 1/2 cup chopped unsalted butter in a microwave-safe bowl. Microwave in short bursts of 10-30 seconds, stirring frequently until melted and smooth. Let the mixture cool slightly for about 5 minutes.

Third Step: Mix Dry Ingredients
In a separate bowl, whisk together 1/4 cup flour, 1/2 cup confectioners’ sugar, and 1/8 teaspoon salt. This dry blend ensures even distribution of sweetness and structure.

Fourth Step: Whisk Eggs and Yolks
In another bowl, beat 2 large eggs and 2 large egg yolks until just combined and slightly frothy. This aeration helps create a light texture without heaviness.

Fifth Step: Combine Batters
Slowly stir the dry ingredients and eggs into the melted chocolate-butter mixture. Mix gently until smooth and uniform, avoiding overmixing to keep cakes tender.

Sixth Step: Fill the Ramekins
Spoon batter evenly into ramekins, filling each about halfway. Add roughly 2 teaspoons of creamy peanut butter into the center of each ramekin, gently pressing into the batter. Top off with remaining batter until approximately three-quarters full. Avoid overfilling to prevent overflow while baking.

Final Step: Bake and Serve
Place ramekins on a baking sheet and bake for 12–16 minutes. Watch closely; edges should be firm but centers remain slightly soft and gooey. For muffin tins or smaller molds, shorten baking to 8–14 minutes. After baking, let cakes cool for 1 minute, then invert carefully onto serving plates. Serve immediately for molten lava effect. Garnish with ice cream, melted peanut butter drizzle, or chocolate syrup if desired.