Cut a piece of parchment to fit the bottom of the tart pan. Spray the tart pan and place the parchment on the removable bottom. Spray the parchment paper and set aside.
Toast the pecans by placing them on a cookie sheet and heating in the oven for 10-12 minutes or until fragrant and browned. Set aside to cool.
Cut the butter into chunks and transfer to a microwaveable bowl or 2 cup glass measuring cup.
Roughly chop 3 ounces of the chocolate and add it to the butter. Microwave in 20-30 second bursts, stirring after each burst until the chocolate and butter are smooth and combined. Transfer the chocolate mixture to a large bowl.
Whisk in the cocoa powder. Add eggs one at a time and whisk after each addition. Add the sugar and whisk into the chocolate mixture. Whisk in the vanilla.
Add the room temperature cream cheese to the chocolate mixture and whisk together until just very small bits of cream cheese remain. Whisk in the flour and salt, combining just until the flour is moistened.
Chop the pecans finely and add to the chocolate mixture. Stir to combine. Transfer the chocolate brownie batter to the prepared tart pan and smooth over with a spatula.
Bake the tart in a hot oven for 35-40 minutes or until a cake tester placed 1" from the edge comes out clean. (Note: interior will be very fudgy and seemingly undercooked.)
FOR GANACHE:
Chop the chocolate very finely.
Heat the cream in a glass measuring cup or bowl in the microwave for 45 seconds to a minute, until very hot.
Add the chocolate to the hot cream and let sit for about 1 minute. Whisk the chocolate and cream together until silky and smooth. Set aside.
ASSEMBLE THE TART:
Butter the handle end of a wooden spoon (about 1/2" diameter).
When the tart just comes out of the oven, press the handle of the greased wooden spoon into the tart, all the way to the bottom, making a twisting motion. Continue to make the divots all over the surface area of the brownie tart, about 1" apart. You should have 24-28 divots.
With a spoon or (if you have a steady hand) pouring from the glass measuring cup, fill each of the divots with the chocolate ganache.
Carefully transfer the tart to a wire baking rack and let cool completely. The ganache will sink as the brownie cools, however, you can continue to fill them with more ganache, if necessary. When the tart is completely cool and the puddles begin to firm up. Spread the remaining ganache over the entire tart and even it out with an offset spatula. If you'd like to decorate with sprinkles or other garnish, do it now.
Rest the tart, uncovered and at room temperature until the ganache has set and is firm to the touch.
When ganache has set, place one hand flat on the bottom of the tart pan and with the other remove the collar. Use a thin offset spatula to wedge between the bottom of the tart pan and the parchment paper. In one quick movement, transfer the tart to a cake stand or platter.
Slice and serve with a scoop of Old Fashioned Vanilla Ice Cream.