Generously grease four 6-ounce ramekins with butter and dust lightly with cocoa powder, tapping out any excess.
In a microwave-safe bowl, melt the chocolate chips and butter together in 30-second intervals, stirring between each, until completely smooth.
In a separate bowl, whisk together the eggs, egg yolks, and powdered sweetener until the mixture becomes thick and pale yellow.
Pour the melted chocolate mixture into the egg mixture and whisk until fully incorporated.
Add the almond flour, vanilla extract, and salt, stirring gently until just combined without overmixing.
Divide the batter evenly among the prepared ramekins, filling each about three-quarters full.
Pour 1 cup of water into the bottom of your slow cooker and carefully place the ramekins inside.
Cover and cook on high for 1.5 to 2 hours until the edges are set but the centers still jiggle slightly when gently shaken.
Carefully remove ramekins using tongs or oven mitts, let cool for 2 minutes, then run a knife around the edges and invert onto plates to serve immediately.