Preheat the oven to 425°F (220°C).
Unroll the refrigerated pizza crust onto a 10 x 15-inch baking sheet lined with parchment paper.
Use a fork to poke holes evenly across the pizza crust. Prebake the crust for approximately 7 minutes.
While the crust is baking, brown the breakfast sausage in a large skillet over medium heat, breaking it into small crumbles as it cooks. Once the sausage is completely cooked, remove approximately half of it from the skillet and set it aside.
Add the butter to the sausage remaining in the skillet. Once melted, stir in the flour.Cook the sausage and flour mixture for 3 to 4 minutes, stirring frequently.
Slowly pour in the half-and-half while stirring continuously. Reduce the heat to low and cook for approximately 3 to 4 minutes, stirring frequently, until the sausage gravy is very thick and spreadable.
Season with ½ teaspoon each of salt and black pepper. Taste and adjust the seasonings if needed.
Remove the gravy from the heat and allow it to cool slightly.
Spread the sausage gravy evenly over the prebaked pizza crust.
Sprinkle the shredded mozzarella evenly over the gravy.
Top with the reserved cooked breakfast sausage.
Return the pizza to the oven and bake for another 8 to 10 minutes, or until the cheese is completely melted and the edges of the crust are lightly browned.