Preheat oven to 350°.
Roast the garlic: Slice the tops off the whole heads of garlic, just enough to expose the garlic cloves, about ¼-inch.
Grease the bottom of a pie pan or baking pan with 1 Tablespoon of olive oil. Place the heads of garlic in the pan, cut side down. Cover with aluminum foil and bake at 350° until the garlic cloves are very soft and tender, about 1 hour. Remove from oven and let cool for 15-20 minutes.
Using the broad blade of a Chef’s knife, mash the roasted heads of garlic to extract the roasted garlic cloves. Set aside.
While the garlic is roasting, cook the navy beans: In a pot, add the water, washed beans, 2 teaspoons of salt, and bay leaf. Bring the mixture to a boil. Reduce heat and cook at a low boil, stirring occasionally, until the beans are very soft and tender, about 1 hour.
Drain the beans, reserving the cooking liquid. Discard the bay leaf. Refrigerate the beans until fully chilled.
In a food processor, add the cooked beans, roasted garlic, Tahini, 1 ½ cups of reserved cooking liquid, 4 Tablespoons of olive oil, the lemon juice, 1 Tablespoon of salt, and cayenne pepper. Process the mixture until smooth.
Serve the Roasted Garlic Hummus with pita bread, chips, or vegetables for dipping.