If making your own pizza dough, allow an additional hour in your prep time for prepping and rising.
When ready to assemble toppings, heat 2 tbsp olive oil in a skillet over medium. Slice sausage links on a bias and toss into pan. Allow to brown slightly on one side, about 3-5 minutes, turn turn and cook an additional 2-3 minutes to brown on the other side. No need to get the meat super crispy since it will continue to cook in the oven. Once nicely golden, remove from pan and scoop onto a plate lined with paper towels to drain.
If you used a real-meat Italian sausage, you probably don't need to oil your pan again. If the skillet looks dry, add another teaspoon of oil and swirl to coat. Toss onion, garlic, fennel, salt and pepper together and caramelize for about 5-8 minutes until soft and fragrant.
Whichever method of dough-making you select, you'll probably need to parbake it. Preheat oven to 450 degrees with either a pizza stone or large (12 inch preferably, or even bigger if you have it) on the rack to preheat as well. Form your dough into your preferred size - I usually get about a 12-inch crust from my homemade formula, though I do like it thinner so 10-12 inch is likely apt - and carefully transfer to your stone or skillet. Brush dough with 1 tbsp olive oil and parbake for 6-8 minutes until slightly firm.
Assemble your pizza - the fun part! Line bottom of the crust with kale, then top with 1/2 cup shredded cheese. Dot evenly with fennel mixture, sprinkle rest of cheese, then top with sausage and basil leaves. Cook for about 10 minutes until cheese melts, then turn broiler to HIGH and cook an additional 2-3 minutes, watching closely, until crust is nicely brown and cheese bubbles. Carefully remove from oven, slice, and serve!