Preheat your oven to 350°F (175°C).
Place the two croissants on a baking sheet, cut side up. Warm them in the oven for about 5 to 7 minutes until they're lightly toasted.
Melt two tablespoons of butter in a medium-sized skillet over medium heat. Crack the four eggs into a bowl and whisk them together until fully combined. Pour the eggs into the skillet and stir occasionally for about 3 to 4 minutes until scrambled and cooked through.
Season your eggs with a quarter teaspoon of salt and a quarter teaspoon of black pepper. Stir them well.
Carefully slice each toasted croissant in half horizontally. Place a slice of cheddar cheese on the bottom half of each croissant, followed by one slice of cooked bacon on top. Spoon scrambled eggs evenly over each half and finish with a small handful of fresh spinach.
Place the top half of each croissant over the fillings, creating a sandwich. Serve immediately while they're warm and melty.