In a mixer with the paddle attachment on low, mix the flour, cocoa powder, sugar, and butter together, blending until sandy.
In a separate bowl, whisk together the yolks, cream, and vanilla extract. Add to the dry ingredients and mix until dough just comes together. Make into disks, wrap, and chill for 30 minutes.
Roll out in small batches, as it gets soft quickly. With a 4-inch round chilled cutter, cut out disks. Keep dough chilled while you roll and cut the rest of the dough. Line 2-inch tart pans or rings with the disks. Line with plastic wrap (that's right!) and fill with rice then gather the plastic wrap up to contain the rice or place a second tart pan on the crust and bake them upside down on a sheet pan. Bake for 14 minutes then remove the rice packets and bake 2 more minutes to crisp. For the upside down version, bake 14 minutes total. Let cool slightly while you make the filling. This will make more dough than you need but it freezes well.
To make the filling: In a small saucepan heat the cream until boiling. Meanwhile place the chopped chocolates in a bowl. Pour the hot cream over the chocolate and whisk until melted and combined.
Pipe a thin layer of peanut butter in the bottom of each cooled crust then pour the ganache to fill up the tart shell completely. Roll the peanuts on the gold leaf to gild them then place 1 peanut in the center of each tart on the surface. Let cool until set about 2 hours, then serve the same day.