I recently removed hardwood flooring from my foyer, dining room and kitchen areas. I stained and faux finished the concrete as my alternative to replacing the hardwood or carpeting. My problem is I have gaps around my door mouldings which are not flat surfaces. ( these mouldings are fluted) The existing quarter round was reattached and is flush with the concrete. I do not know how to trim the doorways because this trim protrudes out past the baseboards. Can you please offer some suggestions?

Plinth blocks. You might have square blocks, carved with, perhaps a rosette or circular pattern in the upper corners of the door casing? Find something you like that matches or even just use blocks of the same species of wood, cut back the height of the mouldings up from the floor and install the blocks at the bottom. The bottom of the jams can be filled in, tricky, but doable, probably easier if one side of the casing is removed to allow even a small backing material to be slid into place.

Or... If the plinth block is as wide as the casing plus the reveal, you could also run a thin door stop type moulding along the bottom of the jams. The bottom of the jams should be lower than the door bottoms so it should not interfere with the operation of the door. You will want to back cut the moulding facing the jams so as to install a return on the edge of each moulding.

Or... You could simply remove the casing from both sides of the doorways, Cut through the fasteners holding the jams into the framing and lower the jams down to the floor with just a thin bead of sealant between the slab and the wood of the jams. If the jams were already touching the slab, cut them the same space as the moulding was kept frpm the floor to allow for floor coverings. Reinstall you mouldings. Might be only a youch of sanding where paint gathered at the top of the casing/wall intersection.

Up to you from here.

Have fun.