Buy a package of bratwurst at your local grocer (extra points for choosing sustainably raised meat!). Pack it into your camping cooler.
Slice 3 yellow onions into thin rings, then add them to a medium-sized saucepan with 4 T butter and 1 T olive oil. Cook over medium high heat for 20 minutes, stirring occasionally, then reduce to medium-low heat and cook for another 40 minutes, stirring even more occasionally. Finish with cracked black pepper and salt and, if you wish, a spoonful of brown sugar. Stir to combine, then transfer to a Tupperware container and add the jam to the cooler.
When you arrive at your campsite, grill the bratwurst however you’d like, until charred. Slide some hot dog buns onto the grill for 2 minutes. Then spread the buns with onion jam and stone ground mustard (I love Trader Joes’ take on this). Top that with a brat and a handful of arugula.