In a large bowl, combine the first seven muffin batter ingredients.
In another bowl, combine the eggs, pumpkin, buttermilk, oil and vanilla. Stir into dry ingredients just until moistened - do not over stir it or you'll get tough muffins. Just a few folds until no flour remains. Set aside while you make the filling and streusel.
Make the Cheesecake Filling
Combine the cream cheese, sugar, egg, salt and vanilla beat until smooth. Do not over beat. Spoon the cream cheese filling into a pastry bag with a medium plain tip or a zip-lock bag with one end snipped off. Set Aside.
Make the Toffee Streusel
In a small bowl, combine the brown sugar, pecans, chopped toffee and flour; cut in butter until crumbly. Place in fridge, covered, until ready to use.
Assemble and Bake the Muffins
Grease the top of the jumbo muffin tins lightly, making sure the area around each muffin well is greased. These babies rise a lot and spread a bit. If you don't use jumbo muffin liners, grease each muffin well too.
Fill the 8 to 10 greased or paper-lined jumbo muffin cups half way with pumpkin batter. Place cheesecake batter filled pastry bag in the middle of each half filled muffin well, and squeeze in the filling until the batter rises and fills the lined muffin wells ⅔ to ¾ths full. Tap the pan on the counter a few times to release air bubbles, which I forgot to do, hence some of the holes in my cheesecake filling.
Cover white circles of cheesecake on top with any extra pumpkin batter, or just scoop the pumpkin batter from the sides or underneath to cover. If you don't care about a big, muffin dome, skip this step.
Dump large handfuls of toffee streusel over cheesecake filled muffin batter. Make sure to keep it contained in the muffin well -mounding it like little mountains. Any that spills onto muffin pan, wipe off or brush into one of the wells. Ignore my raw streusel photos...I wiped all that extra crumb off ;D
Bake at 375° for 25-30 minutes (about 15-18 minutes for standard-sized muffins) or until a toothpick inserted near the center comes out clean. Cool for 5 minutes before removing from pan to a wire rack.
notes:
* If using canned pumpkin, strain puree overnight in a colander, or cook down until thick, bubbly and the moisture is reduced, then cool before adding to batter.
** Sometimes I toast a handful of whole pecans, then chop them and measure ⅓ cup, eating any leftovers, or throw the ⅓ cup of chopped pecans in a pan on the stovetop and stir over low head until fragrant and toasty. Whatever is better for you!
Recipe by parsley sage sweet at https://parsleysagesweet.com/2011/12/09/jumbo-cheesecake-stuffed-pumpkin-muffins-with-toffee-streusel/