In a medium bowl, combine the cocoa powder, and espresso powder. Pour hot water over mixture. Cover and let stand for 5 minutes. Whisk mixture gently until smooth then whisk in butter and set aside to cool.

Meanwhile, preheat the oven to 350°F and line a muffin tin with paper liners. Set aside.

When the chocolate mixture is cool enough to touch, add in egg and yolk and whisk to incorporate. Add in the heavy cream and vanilla and whisk again until smooth.

Add the monk fruit, allullose, almond flour, coconut flour, baking powder, baking soda, and salt. Stir until completely mixed.

Divide the batter evenly between the cupcake liners, filling them no more than 3/4 full. Bake at 350ºF for 20-25 minutes, or until a toothpick inserted into the middle of the cake comes out clean or with only a couple crumbs on it. Remove from oven and let rest for 15 minutes before turning out onto cooling racks. Cool completely before filling and frosting.

Cook the berries - either microwave them until broken down and soft or heat over medium-high heat in a small pan on the stovetop, pressing to break them down. Strain this mixture through a fine mesh strainer if using raspberries and into a small bowl, pressing to extract as much as possible, discard seeds. Stir in the stevia, pinch of salt, lemon juice, and glucomann. Stir well until the mixture is smooth. Set aside, stirring occasionally until cool and thickened.

Combine the butter and cream cheese in a bowl and use an electric mixer (stand mixer or handheld) to beat the mixture until light and fluffy. Add in the cocoa, monk fruit, almond milk, vanilla, and salt. Continue beating to a light yet spreadable consistency, adding more almond milk or cream if desired.

Using a paring knife, cut a small core out of the middle tops of the cupcakes. Spoon in a tablespoon or so of the jam. Finally, transfer the frosting to a piping bag fitted with a piping tip and pipe onto the tops of the cupcakes. Alternatively, you can use a knife to spread the frosting on top as well.