Begin by heating up a large pan over medium-high heat. Once the pan is hot, add a drizzle of oil and the sliced onions. Cook the onions until they start to become translucent and develop a golden brown color, stirring occasionally to prevent burning.

While the onions are cooking, prepare the giardiniera by removing it from the jar and draining off any excess liquid.

Once the onions are cooked, remove them from the pan and set them aside in a separate bowl. Add the red peppers and pickled sport bell peppers to the same pan and cook until they start to soften and char slightly around the edges.

Remove the peppers from the pan and set them aside with the onions.

In the same pan, add the Greenridge Farm German Bratwursts and cook them until they are heated through and develop a golden brown color. Make sure to turn them frequently to prevent burning.

Once the bratwursts are cooked, remove them from the pan and set them aside on a plate.

To assemble the sandwiches, cut the brioche hotdog buns in half and place one bratwurst in each bun. Top each bratwurst with a spoonful of the cooked peppers and onions, and a generous amount of giardiniera.

Finally, spread yellow mustard over the top of the bratwursts to finish the sandwiches.

Serve the German Bratwurst Brioche sandwiches hot and enjoy!