Combine the cream cheese and mozzarella cheese in a microwave-safe bowl. Heat them in 30-second bursts, stirring in between, until completely melted and smooth. This forms your wonderful "fathead dough" base!
In a skillet, heat the olive oil over medium heat. Add the chopped onion and cook until it's soft and translucent. Stir in the minced garlic and cook for just 30 more seconds until fragrant. Remove from heat and let this flavorful mixture cool down.
Once the melted cheese mixture is ready, transfer it to a mixing bowl. Add the almond flour, onion powder, baking powder, one large egg, garlic powder, and xanthan gum. Mix everything together until a smooth, cohesive dough forms. Cover the bowl and chill the dough in the refrigerator for about 30 minutes – this makes it much easier to handle.
While your dough is chilling, mix the cooled onion and garlic mixture in a separate bowl with the raw pork sausage, the remaining large egg, and a pinch of salt and pepper to your taste. Ensure everything is well combined.
Preheat your oven to 400°F (200°C). Take your chilled dough and roll it out evenly between two pieces of parchment paper until it's about 1/4 inch thick. Cut the dough into 8 equal-sized squares or rectangles.
Spoon a generous portion of the sausage filling down the center of each dough piece. Carefully roll the dough over the filling to enclose it, gently pinching the edges to seal them shut.
Arrange your beautifully assembled sausage rolls on a baking sheet lined with parchment paper. Bake for 20-25 minutes, or until they're golden brown and the sausage is cooked all the way through.
Let the keto sausage rolls cool slightly before serving. They're delicious warm or even cold, making them perfect for meal prep!