Preheat oven to 350°F. Line a 12-cup muffin tin with muffin liners.
In a small bowl, combine cream and vinegar; set aside.
In a medium bowl, whisk together all dry ingredients.
In a mixing bowl with hand beaters or a stand mixer, blend butter, oil, eggs, syrup, and sweetener until fluffy.
Add the cream mixture, then slowly add the dry ingredients until combined.
Spoon batter into muffin cups.
In a small bowl, mix topping ingredients; spread over each muffin.
In a small bowl stir the topping ingredients together and spread on about a teaspoon to each muffin top.
Bake 25 minutes, until golden brown and a toothpick inserted comes out clean.
While the muffins are baking , mix the icing ingredients together in a stand mixer until smooth, no lumps. Set aside until muffins are ready.
Allow muffins to cool about 5 minutes then loosen around edges with a butter knife.
Remove to a pie plate if desired to top with Icing and enjoy!
If making ahead, keep muffins and icing in the refrigerator, reheat muffins in oven at 350 for 10 minutes and add icing when ready to serve.