Easy vanilla cake

INGREDIENTS

• 250g pack unsalted butter , softened, plus extra for greasing
• 250g golden caster sugar
• seeds scraped from 1 vanilla pod or 1 tsp vanilla paste
• 5 large eggs , cracked into a jug
• 85g plain flour
• 100g full-fat Greek yogurt (I used Total)
• 250g self-raising flour
• 3 tbsp semi-skimmed milk
• 50g golden caster sugar
• seeds ½ vanilla pod or ½ tsp vanilla paste