Fry bacon in large frying pan until crispy. Remove from pan to plate. Pour out all drippings except for a couple of tablespoons.
Add 1 tbsp butter to bacon drippings. Melt.
Place chopped kohlrabi in frying pan and fry on medium until medium-soft.
Place remaining 4 tbsp of butter, chopped, to pan.
Add brussels sprouts. Gently stir with kohlrabi, place lid on pan, stirring sporadically to prevent sticking. Heat for approximately five minutes.
Squeeze fresh lemon juice over the top. Add salt and pepper to taste.
Heat for another 5-7 minutes, depending on consistency preference for brussels sprouts.
Break up, or chop, crispy bacon and add to pan. Stir and serve.