Streusel topped 'coffee' cakes are extremely popular and this one with a seam of banana and Nutella is no exception. In the US these are commonly baked in 33cm/13″ x23cm/9″ traybake tins. There is a lot of mixture in these recipes and I prefer to make a dozen streusel topped muffins and use a smaller cake pan. Use what works best for you.
This particular combination comes from New York bakery, Ovenly. If I had scaled down the ingredients I could have made it in the Thermomix but I used a stand mixer to use the quantities given below.
banana Nutella streusel cake
225g unsalted butter, melted
60g sour cream
4 large eggs
10g vanilla extract
560g plain/all purpose flour
7 g salt
Pinch baking powder
15g baking powder
430g caster sugar
2 bananas, thinly sliced
150g Nutella warmed in microwave to help spread
45g soft brown sugar
60g unsalted butter, melted
30g soft light brown sugar
150g Plain/all purpose flour
1 tsp ground ginger
1 tsp cinnamon
Preheat oven to 180°C/350°F
Prepare tin 33x23cm / 13″/9″ or muffin tins and a smaller tin
Make the streusel topping and set aside.
To make the batter:
Whisk together the cooled melted butter, eggs, sour cream, buttermilk and vanilla extract
Whisk the dry ingredients, flour, sugar, baking powder,baking soda and salt
Beat the wet ingredients into the dry until well combined
Spread half the mixture on the baking pan or muffin cases.
Lay the banana slices over the batter
Drizzle the Nutella over the banana
Spoon the remaining cake batter over the filling
Lightly press the streusel topping over the batter
Bake in preheated oven for 50 minutes for traybake tin, 20 minutes for muffins
Check for doneness with a skewer.