Preheat oven to 350°F. 

Line a sheet pan with aluminum foil, arrange 6-8 strips of thick-cut bacon in a row and bake until crispy, 20-25 minutes.

Remove the sheet pan from the oven and use a pair of tongs to transfer the crispy bacon onto a platter or plate lined with paper towels to absorb excess grease. Reserve three tablespoons of bacon grease (optional). Set aside. 

Add the collard greens over medium-high heat and 6 cups of water in a large stockpot. Blanche the collard greens until they are bright green in about 5-minutes. 

Place a large skillet over med-high heat. Add bacon drippings, three tablespoons of olive oil, and two tablespoons of unsalted butter. When the olive oil and butter mixture has melted, add the flour and cook until the roux is light blond color.  

Whisk in the heavy cream and whole milk, reduce the heat to low, then add the Hot Old Bay seasoning, smoked paprika, sea salt, and freshly cracked black peppercorns. Whisk until the seasoning until thoroughly mixed.

 Add the chopped collard green, onions, and celery. Stir to mix, then place a lid over the skillet and simmer on low heat, stirring often, until the greens are tender and the sauce thickens. 

When the greens, especially the stems, are tender, turn off the heat and move the skillet to the cool side of the oven.  

Top the creamy collard greens with the thick-cut bacon and green onions.

Serve.