How to Make It
Season chicken on both sides with salt and pepper. Place in a small skillet and pour in cider. Cover and cook over medium heat until chicken is cooked through, about 20 minutes. Remove chicken to a shallow bowl. Increase heat to high and bring cider to a boil. Cook until thick, syrupy and reduced to about 1 Tbsp., about 6 minutes (watch carefully, as it can burn quickly). Pour over chicken. Allow to cool completely.
Combine vinegar, lemon juice, mustard, 1/2 tsp. salt and 1/8 tsp. pepper in a large salad bowl. Whisk until salt has dissolved, then slowly drizzle in both oils while whisking. Whisk until blended and thickened.
Just before serving, cut chicken into 1-inch cubes. Add to bowl with dressing along with any juices that have accumulated in bowl. Add endive, romaine, apple and almonds. Toss well. Season with salt and pepper.