1Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until browned and crisp, about 10 minutes. Drain on paper towels; chop into smaller pieces.
2Place potatoes in a large pot and cover with salted water; bring to a boil. Reduce heat to medium-low and simmer until tender, about 10 minutes. Drain and return to the pot; mash slightly.
3Stir bacon, blue cheese, milk, egg, green onions, salt, and pepper into the pot; mash mixture with a potato masher to desired consistency. Cool slightly, about 5 minutes.
4Pour bread crumbs into a shallow bowl. Shape the potato mixture into twelve 1/2-inch thick cakes; dredge in bread crumbs.
5Heat olive oil and butter in a large nonstick skillet over medium heat. Add 4 potato cakes; cook until browned, about 2 minutes per side. Repeat with remaining potato cakes. Cover and keep warm.
Footnotes
Cook's Notes:
Substitute bacon grease for the olive oil and butter if desired.
The cakes can be made ahead of time and refrigerated. Add 2 minutes per side to cook through.