Step 1

Cook potatoes in boiling water 25 min. or just until tender; drain. Cool until ready to use.

Step 2

Meanwhile, heat oven to 350°F. Cook and stir bacon in large skillet until crisp. Remove bacon from skillet with slotted spoon; drain on paper towels. Discard all but 1 Tbsp. drippings from skillet. Add onions to reserved drippings; cook 5 min. or until onions are slightly softened, stirring frequently. Add aioli and thyme; mix well. Gradually stir in chicken broth. Bring to boil, stirring frequently; simmer on medium-low heat 5 min., stirring occasionally.

Step 3

Cut potatoes into 1-inch chunks. Add to onion mixture in skillet along with the bacon; mix lightly. Spoon half the potato mixture into 2-qt. casserole sprayed with cooking spray; top with 4 cheese slices. Repeat layers.

Step 4

Bake 15 min. or until heated through.