Gather all ingredients. Heat oven to 375F and line an 8x8 baking pan with parchment. Melt the chocolate in a glass bowl on medium heat for 30 intervals, stirring each time until smooth.

Add butter and microwave the bowl for ten seconds. Stir, then repeat until smooth. Set aside to allow to slightly cool while you prepare the batter.

In a large bowl, beat the eggs and granulated sweetener on high until the mixture becomes frothy and the eggs become pale. This should take about 3-5 minutes.

Add the mascarpone cheese and beat until smooth.

Sift in half of the cocoa powder and salt, then gently mix. The power will resist mixing with the egg so go slow and keep at it.

Sift in the rest of the cocoa powder and stir until all of the mixture is dissolved and the batter forms.

Make sure your chocolate is still melted. If not, heat for 10 seconds and stir. Fold the melted chocolate into the batter and mix well until it is creamy and there are no lumps.

Pour batter into prepared pan and bake for 25 minutes or until the center no longer jiggles.

Remove from pan and cool completely before cutting!