Sour Cream Coffee Cake Muffins

Rich and dense and perfectly tasty. Thank you Comfortable Food

For the crumb topping:
3/4 cup all purpose flour
3/4 cup brown sugar
1/4 tsp salt
1/2 cup walnuts
6 tbsp, cold and cut into small pieces

For the cinnamon swirl:
1/2 cup sugar
1 1/2 tsp cinnamon

For the muffins:
3 1/2 cups all purpose flour
1 tsp baking powder
1 1/2 tsp baking soda
1/2 tsp salt
1 cup butter softened
1 1/2 cups sugar
4 large eggs
2 cups sour cream (creme fraiche)
1 1/2 tsp vanilla extract

• In a medium bowl, sift the flour, sugar and salt together, then stir in the walnuts.
• Use a pastry cutter or your fingers to mix the butter in until the mixture looks like coarse bread crumbs.  
• Cover with plastic wrap and put in the refrigerate.
• In a small bowl, mix the sugar and cinnamon together well, then set aside.
• Preheat the oven to 350 F (175 C) 
• Spray a muffin pan well (inside the cups and on the top) with cooking spray.
• Sift the flour, baking powder, baking soda and salt together in a medium bowl, and set aside.
• In a larger bowl, use an electric mixer to cream the butter and sugar together until light and fluffy.  
• Add the eggs one at a time, beating well after each addition.
• Add the sour cream and vanilla, and mix until just blended.
• Add the flour mixture in three equal additions, beating just enough to incorporate after each addition – do not over-mix.
• Spoon the batter into the muffin cups, filling them about two thirds full 
• Sprinkle over a large spoonful of the cinnamon sugar and use a knife to gently swirl it in.  
• Top with another spoonful of batter, spreading it evenly over the top.
• Sprinkle the crumb topping on top of the muffins and bake in the oven for about 25 – 30 minutes, until a toothpick test comes clean.