Mix the dry ingredients in a large bowl. In a separate bowl mix the wet ingredients and add them to the bowl with the dry ingredients. Using a spatula fold the two together until incorporated. Don’t over mix.
Fold in the blueberries then fill 9 muffin paper cups 3/4 of the way full (or your favorite muffin pan or silicone muffin cups).
Make the streusel topping by grating the cold butter over the flour and sugar mixture. Use your fingers to quickly work the mixture together until it looks like wet sand.
Top each muffin with with 1 tbs of streusel topping if desired, or just sprinkle some sugar on top.
Bake for 20 minutes at 375"F or until a toothpick inserted in the middle comes out clean.
Cool in the muffin cups on a wire rack for 10 min.
Notes
If using paper muffin cups you can just tear them around the muffin when ready to eat. If using silicone muffin cups turn them upside down and the muffins will slide out.
Don't overmix the batter - folding the dry and wet ingredients together is key. You can do this!
Storage - even tough there is ricotta cheese in the mix refrigeration is not necessary. You can store the muffins at room temperature for a couple of days loosely covered with aluminum foil. They can also be be frozen individually in plastic bags or wrapped in foil.