It's up to you if you want to toast your soft pretzels! With some soft pretzels, it can make them super hard. You want the pretzels to be almost crouton like, but you don't want them to break your teeth. And the idea with a panzanella is that you let the bread cubes soak up the dressing.
If you wish to toast your pretzel cubes, preheat the oven to 350 degrees F and line a baking sheet with foil. Drizzle a tablespoon or so of olive oil on and toast, tossing once or twice, for 10 to 12 minutes. Let cool completely before making the salad.
Heat a skillet over medium heat and add the bacon. Cook, stirring occasionally, until it is crispy and all the fat is rendered. Remove the bacon with a slotted spoon and place it on a paper towel to drain excess grease.
Remove all but 1 tablespoon bacon grease from the skillet and add the onion. Add a pinch of salt and pepper. Stir to toss. Cook over low heat, stirring often, until the onion begins to caramelize. This can take 30 to 40 minutes, but if you're in a rush, you can speed up the process by adding 1 to 2 teaspoons of sugar, honey or maple syrup. I like my onions to be super dark and caramely and delicious! Stir in the garlic about 5 minutes before finishing the onions. Once the onions are finished, transfer them to a bowl.
Add 1 more tablespoon of the bacon grease back to the skillet and add the brussels sprouts. Add another pinch of salt and pepper. Cook, stirring often, until they become golden and slightly charred in spots, about 6 to 8 minutes. Everything should be ready to go at this point!
To assemble the salad, place the pretzel croutons in a large bowl. Drizzle about three quarters of the dressing on the cubes, tossing well. Let them sit for 5 to 10 minutes. Add the remaining ingredients - your brussels sprouts, apples, caramelized onions and bacon and toss well. Drizzle on the remaining dressing if you wish. Taste and season additionally if needed!
Serve immediately and go to heaven.