First, get your onion caramelizing: Dice or slice your onion and put it into a skillet with a tablespoon of oil, a ¼ cup of water and a teaspoon of salt. Turn the heat low and stir it occasionally until it browns and caramelizes, around 20 minutes.

Make your aioli by separating 2 eggs. Reserve the whites for a different purpose and drop the 2 yolks in a large bowl. Add 1 teaspoon of Dijon mustard and 1 teaspoon of salt. Whisk together and slowly add in a constant stream 2 cups neutral oil such as grapeseed or canola and ¼ cup olive oil. Take your time whisking in the oil so the emulsion doesn’t break. This can take some time. Take breaks between adding the oil to whisk the mixture well. Add a splash of lemon juice, 1 or 2 grated garlic cloves and adjust the salt if needed. (The extra will keep in the fridge up to 4 days and can be used for a million things—dips veggies in it, make deviled eggs, spread on sandwiches, make an onion dip, etc.)

Assemble your panini. Lay out 4 slices of sourdough bread. On two, spread the Dijon and on the other two spread the aioli. For each of the two sandwiches, add 1 slice of cheddar, arrange kielbasa slices on top of the cheddar. Divide the caramelized onion between both panini. Sprinkle on the sauerkraut. Top with another slice of cheddar. Close those bad boys up with the other slice of bread. Toast them slowly in a buttered or oiled pan until the cheese melts. Weigh them down with a heavy pan to get a “panini’d” feel. Slice in half and enjoy with a friend!