Step 1Combine lemon juice with water in 13x9-inch baking dish. Add apples to lemon water as you slice them to prevent browning. Sprinkle apples with sugar and dot with butter.
Step 2Cover dish with foil and bake at 375 degrees, stirring occasionally, until apples are very soft, 30 to 40 minutes.
Step 3Cool slightly, then pass apples through a food mill. Adjust flavor depending on sweetness of apples, adding sugar or lemon juice to taste.