Place the 12 tablespoons butter, C&H® Golden Brown Sugar, C&H® Granulated Sugar, cinnamon, nutmeg, ginger and cloves in an electric stand mixer fitted with the paddle attachment and mix on medium until creamy and well blended, about 4-5 minutes. With the mixer on low add the eggs, one at a time, mixing each completely before adding in the next. Add in the pumpkin and vanilla and mix for 1 minute more. Periodically scrape down the sides and bottom of the bowl to make sure everything is well blended.
In a medium bowl whisk together the flour, baking powder, baking soda and sea salt. Add to the pumpkin mixture in two batches, alternating with the milk, mixing on low and stopping when just combined. Let the muffin batter sit for 30 minutes.
Preheat the oven to 375F (190C) and line every other muffin well with a muffin liner. Fill each muffin liner almost to the top with muffin batter and cover the tops with streusel. Fill the empty muffin wells with hot water about ½ full. Be careful transferring the tray to the oven, you don’t want to splash water into the muffins.
Bake for 20 minutes in the center of the oven or until a toothpick comes out clean and/or they bounce back when gently pressed in the center. For best results, bake one tin at a time. Let cool in the muffin tin for about 10ish minutes, then use a butter knife to help get them out to finish cooling on a rack.