Combine wine, apple juice, sliced apple, sugar and cinnamon sticks in a large non-reactive pot. Stick cloves into the lemon, then slice the lemon and add to the pot as well.
Place on the stove, set over medium-high heat, and slowly bring to a light simmer. Let simmer for about 20 minutes, until the apples are tender. (Taste to see if you want more sugar. If you want the wine to taste less alcoholic, turn up the heat and let the wine boil for a few minutes.)
Remove from heat and pour wine into heat-resistant glass mugs. Garnish each drink with fresh cinnamon sticks, apple and lemon slices and serve warm.To store, strain leftover mulled wine and keep it in the refrigerator for up to a day. Reheat it slowly on the stove.
Notes
The amount of sugar you need really depends on the apples and juice used. Because I use Granny Smith apples, which aren’t really sweet, I need more sugar. But if your apples are super sweet, you can easily use less. The mugs I use are my favorite, from La Rochere.