To Make the Smashed Potatoes
Melt 3 tablespoons butter in heavy small skillet add leeks and saute over medium heat until limp but not browned. (Set aside a couple of spoonfuls of leeks for garnish if desired).
Add garlic and sauté 1-2 minutes; do not brown. Take off heat and mix in bacon and thyme; cook for one minute; take off heat and set aside.
Cook potatoes in large pot of boiling salted water until tender, about 20 minutes. Drain. Return potatoes to pot and mash roughly; these are not meant to be the consistency of regular mashed potatoes. I actually use a metal mallet meant for tenderizing meat to literally smash them.
Add leek, garlic and bacon mixture, half and half and remaining 3 tablespoons butter and sour cream and mash together. Season with salt and pepper.
Making the Potato Cakes
Mix the Panko crumbs and Parmesan and spread on a plate.
Add the eggs to the smashed potatoes and mix thoroughly. Season with salt and pepper.
Refrigerate for 30 minutes (not an absolute but if you have the time, do it)
Melt equal amount of butter and olive oil in the bottom of a skillet; measure out 1/2 cup of smashed potatoes for each cake and lightly smash in a disk.
Fry over medium heat until warmed throughout and crispy on the outside.
Garnish with a spoonful of leeks if desired and serve warm.