In a large, deep skillet, melt the butter in 2 tablespoons of the olive oil. Add the onion, artichoke hearts, shiitake caps, carrots and garlic and cook over moderately high heat, stirring occasionally, until lightly browned, 7 minutes. Add the chickpeas and stock, season with salt and pepper and bring to a boil. Simmer over low heat until the vegetables are tender and the liquid is nearly evaporated, 5 minutes. Stir in the parsley and chives and keep warm.