1. Gather all ingredients and equipment needed.
To make beer bratwurst:
2. In a large pot, on medium-high heat, add bratwursts and 1 bottle of beer and braised for 10-12 minutes. Remove from heat. Finish on a grill or a ridged cast iron skillet to make grill marks.
To make potato “kraut”:
3. Rinse yellow potatoes and pat dry with a paper towel, peel and hold in cold water. Using a mandolin with a julienne blade attachment or using a large sharp knife, slice yellow potatoes into thin matchsticks and place them in a bowl with cold water.
4. In a small pot, add rice wine vinegar, salt, sugar, caraway seeds, and juniper seeds and heat just until salt and sugar dissolve, then remove from heat and add thinly sliced potatoes, let par-cook in liquid for 1 minute then add ice to the pot to cool down the temperature. Once cooled down, drain the liquid, and set aside the potatoes.
To make caramelized onions:
5. In a frying pan or skillet, on medium heat, add olive oil and coat the pan evenly, then add onions and cook for 30 minutes, occasionally stirring and spreading onions evenly. When the bottom of the pan gets dark with the brown bits, deglaze the pan with water and stir to get brown bits off the bottom of the pan, as needed. Onions will be brown in color when done.
To make whole-grain mustard aioli:
6. Add mayonnaise, whole grain course mustard, parsley, thyme, salt, pepper, and lemon juice in a medium bowl. Mix until fully incorporated.
7. In a frying pan or skillet, add a little oil or butter on medium heat and heat potato buns.
8. Place caramelized onions on the potato bun, then add grilled beer bratwurst, top with potato “kraut” and sliced red onions and dill, then dollop with whole grain mustard aioli.