Preheat the oven to 180°C (350°F) and line 2 cupcake trays with 24 cupcake liners.
Add the oil, eggs, and sugar to a bowl of a stand mixer fitted with a whisk attachment. Beat on medium-high speed until combined, about 2 minutes.
Sift together the salt and flour and add the dry ingredients to the egg mixture. Beat at low speed until just combined.
In a jug combine the milk and vanilla, and slowly pour this into the cupcake batter with the motor of the mixer running at low speed. Scrape down the sides of the bowl and mix again, making sure it is lump-free.
Fill 24 cupcake liners with the cupcake batter, filling them ¾ of the way up the liner. Bake in a preheated oven at 180C (350F) for 12 – 15 minutes or until a toothpick inserted into the center comes out clean. Cool completely on a wire rack.
Strawberry Sauce
Wash and chop the strawberries.
In a small pan set over medium heat, add the chopped strawberries, lemon juice, and castor sugar. Heat until the sugar has melted and the strawberries soften.
Use a potato masher to macerate the softened strawberries. You want the strawberries to be chunky but small enough to pass through a piping bag.
Use a measuring cup to remove a ⅓ cup of the strawberry mixture from the saucepan and blend it in a food processor until smooth. Place the remaining strawberry mixture into a piping bag and allow both to cool to room temperature. You can put them in the fridge if you are in a rush.
Strawberry Buttercream
In a bowl of an electric mixer fitted with a paddle attachment, add the butter and icing sugar. Beat at medium speed until the mixture looks like fine breadcrumbs.
In a jug combine the milk and vanilla, with the motor of the mixer running at low speed slowly add the milk mixture. Continue until it has all been added. Then increase the speed of the mixer to medium-high. Beat until light and fluffy, scraping down the sides of the bowl as you go.
Add ⅓ cup of smooth strawberry sauce to the buttercream and beat until just combined. Place the buttercream into a prepared piping bag.
Using an apple or cupcake corer remove the center of each cupcake. Fill the middle of the cupcake with the chunky strawberry sauce and swirl the top with strawberry buttercream. Decorate with fresh strawberries and edible flowers.