Grease a slow cooker with cooking spray. In a small saucepan, melt the butter and unsweetened chocolate over low heat, whisking occasionally. Remove from heat and allow to cool.

In a small bowl, whisk together the heavy cream, instant coffee, and vanilla extract.

In a separate bowl, combine the cocoa, almond flour, and salt.

Beat the eggs with an electric mixer on high speed until slightly thickened. Gradually add the granulated sweetener.

Beat on high for about 5 minutes, or until the mixture is thick and pale yellow.

Turn the mixer speed down to low and slowly add into the melted chocolate mixture.

Stir in the cocoa, almond flour, and salt mixture.

Turn the mixer to medium speed and slowly add the cream, coffee, and vanilla mixture.

Transfer the batter to the prepared slow cooker.

Place a paper towel over the opening of the slow cooker before placing the lid on top to absorb condensation.

Cook on low for 2–3 ½ hours, periodically checking the cake after the 2-hour mark. When done cooking, the center will have a soft soufflé consistency, while the edges will be more cake-like. The center of the cake should be slightly damp on top but resist slightly when pressed. The center of cake needs to reach at least 160F.

Serve and enjoy!