Butter cake –

1. Mix dry ingredients together in a large bowl using a whisk.
2. Whisk together vanilla extract, yogurt, and eggs. Add melted butter and whisk again.
3. mix wet  and dry ingredients and fold together with spatula until combined. Cover and Set in a warm location  until batter has risen by 50% from 1 to 1.5 quarts.
4.  butter a  9-inch spring form and dust with flour.  allow to rise for another hour.
5. bake at 350° until a toothpick comes out clean.

Custard filling-

1. Put the cornstarch in the bottom of a medium sized saucepan and add just enough water to hydrate(¼ cup) add the rest of the ingredients all at once and begin to whisk hard adding just enough water to make a thick paste.
2. Gradually add more water and then until mixture starts to loosen and add the rest whisking well to combine. Turn the heat to high and constantly whisk as the mixture heats. It will begin to steam around 140 degrees and then start to thicken and gelatinize around 170-80 dergees.
3. Whisk hard as the mass becomes thick and difficult to stir. Continue to stir hard for 1 minute while the starches fully gelatinize.
4. Remove from heat and put one tsp of the custard on a plate and into the fridge to chill. Once cooled you can check what the room temperature viscosity will be.
5. If it is not thick enough mix 2 tbs cornstarch and 2 tbs water into a slurry and pour into the custard while whisking. Simmer for  another minute and remove from heat and repeat fridge test.
6. Allow custard to cool and use when room temperature or cooler.

Ganache-

1. Heat in a small sauce pan just until fully melted stirring the whole time.
2. allow to cool for 1-2 hours before frosting cake.

Split cake in half. Fill with custard. Top with ganache. Dust with powdered sugar and raspberries, and serve!