1. Preheat your oven to 350*F. Line a standard 12 cup cupcake pan with paper liners.
2. Add the flour, sugar, baking powder and salt to your mixer bowl and whisk well to combine.
3. Add the cream, oil, buttermilk, egg, egg white, vanilla and lemon zest. Mix on low until combined.
4. Scrape the bowl and paddle and then mix on medium speed for one minute to aerate the batter.
5. Scrape bowl again and then mix on low speed for one minute.
6. Divide the batter between the 12 paper liners. Drop about 6-8 blueberries onto the surface of the batter of each cupcake and push berries down slightly.
7. Tap the pan on the counter 3-4 times. Bake for 20-25 minutes or until a toothpick inserted in the center of the cupcakes comes out clean. Cool cupcakes in pan for 10 minutes before removing from the pan and cooling completely on a cooling rack.
8. To make the cream cheese frosting begin by beating in a mixer bowl the 6 Tablespoons soft unsalted butter until smooth.
9. Add the pinch of fine salt, vanilla extract and cream cheese and beat until smooth and lump free.
10. Scrape the bowl and paddle and then mix in 3 cups confectioners sugar on low speed. Scrape the bowl again and whip on high speed until smooth. Chill frosting before piping if it is too soft.
11. Frost the cupcakes with a spatula or piping bag. Place a few blueberries on top of each cupcake. Chill the cupcakes while making the oat crumble (which is optional.)
12. Make the oat crumble by adding the oats, butter and salt into a skillet and cooking over medium heat, stirring frequently, until the oats are fragrant and have darkened slightly. This takes 2-3 minutes.
13. Turn off the heat, sprinkle the sugar over the oats and stir to combine. Transfer to a plate to cool for 10 minutes.
14. Finish the cupcakes with the oats by picking up a small handful of toasted oats and rolling the edge of the chilled cupcakes into the oats.