Cut the stems and leaves off the kohlrabi bulbs.
Cut the stems into 1/4 inch pieces. Rough chop the leaves into 1-inch strips.
Heat olive oil and butter in a large skillet over medium-high heat.
Once the butter is bubbling, add the diced onion. Sauté for 5 minutes, stirring occasionally.
Then add the chopped stems to the pan and sauté for 3 minutes.
Add the minced garlic and allow to sauté for 30 seconds, stirring often.
Add the kohlrabi leaves to the pan and toss to combine. Allow the leaves to cook for 5 to 7 minutes or until they are tender, stirring occasionally.
Remove the pan from the heat and stir in the lemon juice, salt, and pepper.