Preheat oven to 350F. Grease a 9x13 inch baking dish and set aside.
In a large bowl, stir all ingredients - but only half of the condensed milk - until combined. Smush the softened butter to the sides of the bowl to make sure it is incorporated.
Pour the batter into your prepared dish and bake for about 1 hour or until the edges start turning puffy and golden brown and the centre is set. It's okay if the top of your cake is still bubbling.
Carefully remove the cake from the oven - keep the oven on - and spread the rest of the condensed milk on top. Try to spread it as evenly as you can.
Continue to bake your cassava cake until the top is caramelized. You can also choose to broil on low for a few minutes to help with the caramelization. Just remember to watch your cake because broiling can easily burn it.
Remove from oven and allow to cool in baking dish before cutting into squares and serving. Best served warm.
When dividing your condensed milk, simply eyeball it. Pour half into your cassava mixture and reserve the other half for your topping.
If you want clean, perfect squares, it’s best to cut the cassava cake once it’s fully cooled. In the photos, I achieved those clean edges by refrigerating the cake first before cutting. It’s best served warm though so I just microwave the slices for 20 seconds or so out of the fridge.