Start by cooking the bacon in a skillet over medium heat. Let it get crispy, which usually takes about 5-6 minutes. Once done, transfer the bacon to a paper towel-lined plate to absorb excess fat.

In the same skillet, use some bacon grease for flavor. Add the minced shallots and sauté them for about 2-3 minutes until they're softened. This creates a savory base for your eggs.

In a large bowl, crack open the eggs. Add milk, salt, and pepper. Beat them together until well mixed. This will be the fluffy filling for your sandwiches.

Pour the egg mixture into the skillet with the shallots. Stir gently to scramble the eggs over medium-low heat. Remove the skillet from the heat when the eggs are just set. This should take about 4-5 minutes.

Spread butter on the toasted English muffins. Layer each muffin half with eggs, bacon, spinach, and top with a slice of sharp cheddar cheese. Cover with the other half of the muffin.

For an extra crunch, you can place the assembled sandwiches back into the skillet or a panini press for another minute until the cheese is melted and the exterior is golden.