In a small saucepan, bring 3 cups broth and cider to a gentle simmer over medium-low heat. Cover and keep warm.
In a large, deep skillet, heat oil over medium heat. Add onion; cook and stir until softened, about 4-5 minutes. Add garlic and crushed red pepper; cook until tender and fragrant, about 1 minute. Add rice and salt; increase heat to medium-high heat. Cook, stirring, for 2 minutes. Add wine and stir, allowing to cook until wine is absorbed.
Add 2 cups of the warm broth mixture. Reduce heat to medium-low and stir often until liquid is absorbed. Continue adding additional broth mixture, ½ cup at a time, stirring often until liquid is absorbed. Cook until rice is al dente and mixture is creamy (about 25 minutes total).
Stir in apple, thyme, butter, Parmesan, vinegar, and lemon zest. Add some of the extra stock, if needed, to loosen. Season to taste with black pepper; serve immediately.