In a mixing bowl, crack the eggs and add the milk, salt, and black pepper. Whisk together until fully combined and slightly frothy. This helps to incorporate air into the eggs, making them fluffy when cooked.

In a skillet over medium heat, cook the breakfast sausage. If using bulk sausage, form it into 4 equal patties. Cook for about 5-7 minutes on each side until browned and fully cooked (internal temperature should reach 160°F). Remove from skillet and set aside.

In the same skillet, reduce the heat to low and pour in the egg mixture. Gently stir with a spatula, scraping the bottom of the skillet to prevent sticking. Cook for about 5-7 minutes until the eggs are just set but still slightly soft. Remove from heat.

Preheat the oven to 350°F (175°C). Spread butter on the cut sides of the English muffins and place them on a baking sheet, cut side up. Toast in the oven for about 5-7 minutes until golden brown.

On the bottom half of each toasted muffin, place a sausage patty, followed by a generous scoop of scrambled eggs, and top with a slice of cheddar cheese. Place the top half of the muffin on each sandwich.

Wrap each sandwich tightly in plastic wrap or place them in meal prep containers. Store in the refrigerator for up to 5 days. To reheat, unwrap and microwave for 1-2 minutes or until heated through.