Preheat oven to 425°F/218°C.
Prepare a standard muffin tin tray with 6 muffin liners.
In a medium-sized bowl, whisk together the flour, baking powder, baking soda, salt. Set aside.
In a separate bowl, whisk together vegetable oil, egg, granulated sugar, buttermilk, yogurt and vanilla extract.
Pour the wet ingredients into the dry ingredients and use a spatula to gently fold the mixture together.
With some lumps of flour left, add in the flour-dusted cut strawberries and continue to fold it in until just incorporated.
Be careful not to overmix.
Add 1 tablespoon of batter into each muffin well, filling it about ⅓rd of the way up.
Add a tablespoon of jam to the centre of the muffin batter.
Top off each muffin tin with about 1.5 tablespoon batter, or enough just to cover the jam. Repeat with the remainder of the batter.
Give the muffin tray a few taps to release any trapped air bubbles.
Bake at 425°F/218°C for 5 minutes, and then reduce to 375°F/191°C to bake for another 12-15 minutes, until the tops are golden brown and a toothpick inserted comes out clean or with the slightest crumbs clinging onto it.
Let cool in the muffin tin for 5 minutes before transferring to completely cool on a wire rack.