In a large pot, heat 3 tablespoons of olive oil over medium-high heat. Sear the corned beef pieces on each side.
Slowly add the seasoning packet (included with corned beef brisket), broth, beer and brown sugar. Bring to a boil, reduce heat to a simmer. Cover and cook for 2 ½ hours until the beef is tender. Remove the beef and reserve.
Add the cabbage halves and, if needed, enough water to cover the cabbage. Bring to a boil, simmer for 15 minutes until tender.
Meanwhile, cut the potatoes into quarters, place them in a medium saucepan. Cover with water and 1 tablespoon salt. Bring to a boil, simmer for 15-20 minutes until fork tender.
Drain the potatoes, return to pot and add the heavy cream and butter. Mash the potatoes to desired consistency. Stir in the spinach, cheese, 1 teaspoon salt and pepper.
To make cabbage mashed potato bloom: Remove the cabbage from the braising liquid and make eight 3 ½ x 3 ½-inch round bases with the leaves. Fill each center with ¼ cup mashed potatoes.
Slice the corned beef and serve with bloom. Top with remaining broth.
*These are ALDI Find items that are only in stores for a limited time and may no longer be available.