Pre-heat oven to 180°C.
Using a rolling pin or your hands, gently flatten bread slices just a little. Cut on a diagonal (or use a cookie cutter to cut large rounds larger enough to cover the muffin hole). Remove crust for a well rounded shape or for a home-style, more rustic look (my favourite) leave crust on.
Press each piece into a lined standard muffin tray. Making sure the bread overlaps and comes to the edge. Patch any gaps press into shape.
Sauté spinach in olive oil to soften. Set aside.
Cook bacon in a frying pan (or under the grill with your oven already on).
Line each cup with a spinach and bacon slice and crack over an egg into each.
Season with salt and pepper. Sprinkle with chopped chives or spring onion.
Bake until egg whites are set. Approx. 20 minutes.
Run a small knife around edges to loosen toast.
Serve fresh and warm.