In a large skillet, heat olive oil over medium-high heat. Add cabbage and onions and cook, stirring occasionally, about 5 minutes. Add the apples and continue cooking the mixture for another 5 minutes, stirring occasionally.
Stir in the maple syrup, vinegar, mustard, thyme, salt, and pepper. Reduce heat to low and cook, stirring occasionally, until the cabbage is tender (about another 8 minutes). Remove from heat, cover, and keep warm until ready to serve.