Rub hen breasts with salt, pepper, and cinnamon. Let sit for 10 minutes.
Preheat oven to 350 degrees F. Dice 3 sweet potatoes. Heat skillet, add sweet potato with butter and ginger. Toss until lightly brown. Place in the oven and roast until slightly al dente. Reserve.
Combine sugar, water, and cranberry, and Port wine in same pot. Reduce slowly until thick. Puree and put through chinois. Put back on the stove and reduce until syrupy. Reserve.
Add risotto to pan. Add Riesling. Scrape 1/2 vanilla bean, stirring until incorporated. Add mascarpone. Fold in roasted sweet potato.
Sear off game hen breasts and finish in oven, keeping tender and juicy. Blanch orange zest in hot water for approximately 2 minutes.
Put risotto in the bottom of a bowl or plate, with game hen breasts crossed on the top. Garnish with crispy sweet potato, toasted walnuts, chervil, and drizzle with cranberry syrup. Top with orange zest.