Optional: if you're using curly or Lacinato kale and would like it to be more tender, massage it with a teaspoon or two of olive oil and a pinch of salt. Leave it to sit in the salad bowl while you assemble the rest of the salad.
Place a preferably cast iron frying pan over medium heat and add bacon lardons to cold pan. Fry until bacon reaches desired level of doneness. Remove to a paper towel-lined plate.
Mix the salad dressing. You may either add the oil, vinegar, salt, pepper, and sugar to a mason jar and shake vigorously until emulsified, or you may combine the vinegar, salt, pepper, and sugar in a bowl and slowly stream in the olive oil while whisking vigorously. Set aside. The dressing recipe may be doubled or tripled if desired, and will keep for 2 weeks in the fridge.
Grate the cheddar cheese and chop the apples - do not cut apples until you are almost ready to dress the salad, so that they do not brown.
Assemble the salad: toss the kale leaves with the salad dressing, then add the bacon, cheddar, apples, and roasted pecans. Mix everything together and serve.