In a 6 x 3 heatproof container, whisk together tomato sauce, vinegar, curry powder, paprika, sugar, and cayenne pepper. Stir in onions.
Slice the bratwurst on the diagonal into 1 inch thick pieces. Add bratwurst into the sauce and stir well.
Place the pan in the air fryer basket.
Set the airfryer to 400F for 12 minutes until the sausage is cooked and the sauce is bubbling.
Pre-heat the air fryer before adding the sausage to cook.
Slice the bratwurst on the diagonal and into similar sized pieces so they cook evenly.
Coat the sausage in the sauce so that everything is covered.
If you do not have an air fryer, you can bake this in the oven for 15 minutes. You can also just make this on the stovetop if you prefer. The key is to slice the sausages, and then cook the sausages and the sauce at the same time, so that you are always practicing #ruthlessefficiency in your cooking.