Pre-heat the oven to 180°C.
Line a 12 tin muffin tray with paper muffin cases. Combine the flour, sugar, salt and baking powder in a large mixing bowl. In a separate mixing bowl, whisk together the butter, yogurt, eggs and vanilla extract until smooth. Pour into the dry ingredients and mix together until just incorporated.
Spoon into the muffin cases and bake 15-18 minutes until risen, golden and springy to the touch. Remove and allow to cool on a wire rack.
Once cool, brush the tops of each muffin with the warmed apricot jam using a pastry brush, then sprinkle the rolled oats on top so that they stick to the muffins. Allow them to set before serving.