Preheat the oven up to 365 degrees F.
Prepare the tart molds wiping them clean with a towel.
Mix the egg, butter, sugar, mayo, and vanilla. Add a tablespoon of vinegar to the baking soda and mix. Add to the rest of the ingredients. Mix well. Add the flour and mix thoroughly.
Press your ready dough against the sides and bottom of the tart molds.
Bake the tarts for about 20 minutes until they turn golden in color.
Once ready, turn the molds upside down to lift the tarts. They should come right out. Continue with the remaining dough until you have made enough. Put them aside to cool down.
Melt chocolate over a double boiler.
With the tarts cooled, brush them with coffee both on the top and inside.
Dip them in the melted chocolate and fill the inside of the tart with chocolate spreading it evenly.
Set them aside for the chocolate to settle.
Beat the mascarpone, cream cheese, vanilla, and powdered sugar until mixed well.
In a separate bowl, beat the heavy whipping cream until it's stiff.
Add whipping cream to the mascarpone mix. Gently mix them and refrigerate them until needed.
Use a decorating bag to pipe the cream into the tarts. You can also use a spoon for this process.
Keep refrigerated.
Serve them chilled.
Enjoy!