Chop kale, Brussels sprouts, and red cabbage finely.
If you have access to a mandolin, I highly recommend it to slice fennel and red onion into finely-sliced rings.
Heat a skillet over medium-high heat. Add all vegetables in and cook for 5-7 minutes until the veggies are al dente.
Add lemon juice, olive oil, salt, and pepper and mix together.
Remove from heat and garnish with crème fraîche and caviar.