Wilted Spinach: In a medium nonstick oven-proof skillet, heat butter over medium heat; cook garlic for 1 minute. Add spinach; sprinkle with salt and pepper. Cover and cook for 3 minutes or until wilted. Transfer to a dish and keep warm. Wipe out the skillet.
Preheat the broiler on low. Spread butter evenly over both sides of each slice of bread. Cut a 2-inch hole in the center of each slice.
Heat the same skillet over medium heat; cook bread slices and cutouts for 2 minutes or until golden brown on the bottom. Flip over and crack the egg into each hole. Cook for 2 or 3 minutes or until bread is golden brown and egg is set on the bottom. Transfer cutouts to small dish; set aside. Season eggs with salt and pepper.
Transfer skillet to oven; broil for 3 to 5 minutes or until eggs are set.
Lemon Hollandaise Sauce: Meanwhile, in a small saucepan, melt butter over medium-low heat. Combine egg yolks, lemon juice and mustard in a blender; pulse until smooth. With the motor running, very slowly pour butter into the blender. Stir in lemon zest, salt and pepper. (If desired, cover and let stand at room temperature for up to 15 minutes.)
In the center of each of 4 plates, place a mound of spinach. Arrange egg in-a-hole and cutouts on top of the mound but slightly off to the side. Drizzle with sauce and sprinkle with chives. Serve immediately and enjoy your Egg in a Hole with Spinach & Lemon Hollandaise Sauce.