1. In a large, deep skillet, heat 1 tablespoon of the olive oil until shimmering. Add the chopped chard stems and cook over moderately high heat, stirring frequently, until crisp-tender, about 4 minutes. Add the garlic and cook until fragrant, about 1 minute. Add the chard leaves and cook, tossing, until wilted, about 3 minutes. Drain the chard and transfer to a bowl. Season with salt and pepper. Wipe out the skillet.
2. In a saucepan, bring the stock to a simmer. Heat the remaining 1 tablespoon of oil in the skillet until shimmering. Add the onion and cook over moderate heat, stirring frequently, until softened, about 7 minutes. Add the rice and cook, stirring until the rice is coated with olive oil, about 2 minutes. Add 1 cup of the hot stock and cook, stirring frequently, until the rice has absorbed most of the stock, about 3 minutes. Continue to cook the risotto, adding 1 cup of stock at a time and stirring constantly between additions until the stock is absorbed. The risotto is done when it is creamy and the rice grains are just tender, about 20 minutes.
3. Remove the risotto from the heat and stir in the cheese, butter and cooked chard. Season with salt and pepper and serve at once.
Wine Recommendation: A rich Chianti Classico will echo the creamy texture of the Gouda and soften the sharpness of the greens. Try one from the 1998 vintage, such as the Fontodi or the Vignamaggio.