Fresh Strawberry Cupcakes

Cut the stems off the strawberries and place them all into a food processor. Pulse at full speed until they're completely blended.
1 lb fresh ripe strawberries
Pour the strawberry puree into a small pot and place over low heat for about 30 minutes, stirring occasionally so it doesn't stick.
The strawberries should reduce by about half so you should have 1/2 lbs or 8ish ounces left. Pour it into a jar or bowl and let it come to room temperature. I placed mine over an ice bath and set it in the fridge while I went through all the next steps; it cooled by the time I got to the step I needed it in the recipe.

Slice the strawberries about 1/8-1/4 inch thick - just thin slices and place them in a small bowl with the sugar. Mix them together and place the bowl in the fridge until we need it.
6 small or medium strawberries, 1 Tbsp (12g) granulated sugar

Preheat the oven to 350F/177C convection (325F/163C conventional) and line 12 muffin tins with cupcake liners (preferably a light colored pan).
In a medium bowl, whisk together the cake flour, baking powder, salt and sugar until they're evenly distributed (whisk well).
172 grams (1 1/2 cups) cake flour spooned and leveled, 1 1/2 tsp baking powder, 1/4 tsp fine sea salt, 200 grams (1 cup) granulated sugar
Add the oil and butter to the dry ingredients and beat together until they're combined.
60 mL (1/4 cup) canola oil, 56 grams (1/4 cup) unsalted butter room temperature
Add the egg and vanilla extract and paste and mix until they're fully combined.
2 large (60g) egg whites, 2 tsp vanilla bean paste
Add the sour cream and strawberry reduction and turn the mixer to medium speed just until they're mixed in. Scrape the edge of the bowl and mix just until the cupcake batter is fully combined and smooth.
56 grams (1/4 cup) sour cream, 4 ounces (1/2 cup) strawberry reduction room temperature
Fill each cupcake liner about 2/3-3/4 full, about 55-60 grams of batter per cupcake.
Bake for 16-18 minutes. They are done when you press on the center of the cupcake and it springs back or when a toothpick inserted comes out clean.
Remove them from the oven and let them cool in the cupcake pan for 10 minutes, then move them to a cooling rack. Allow the cupcakes to cool completely before frosting.

Place the butter into the bowl of a stand mixer (or just a large bowl with a hand mixer) and beat at full speed using the whisk attachment. Scrape the edge of the bowl and beat it again until it's pale and fluffy.
227 grams (2 sticks/1 cup) unsalted butter room temperature
Add the powdered sugar and salt and beat at low speed just until the sugar is dissolved. Then increase the speed to medium-high for 1-2 minutes, scraping the edge of the bowl halfway through.
480 grams (4 cups) powdered sugar spooned and leveled, tiny pinch of fine sea salt
Add the vanilla and the strawberry reduction and turn the mixer up to medium-high speed, just until it's combined. Scrape the edge of the bowl well and mix one more time.
2 ounces (1/4 cup) strawberry reduction room temperature, 2 teaspoons vanilla bean paste
Use a piping bag fit with a large round piping tip to frost the cupcakes. Use a small spoon or small offset spatula to create a little swirl on top and top with 1-2 slices of macerated strawberries.