Disregarding the visual effect, you might consider that coconut oil melts at approx. 24°C (76°F), while cocoa butter melts at approx. 33°C (92°F). At room temperature, coconut oil would be dripping off the cake.
Using 240ml/8 oz measuring cups and 15ml tablespoon
180 g chai tea ...3/4 cup
20 g milk ....... 1 1/2 tablespoons [smidgeon over]
125 f butter .....1/2 cup
60 g walnuts .....1/2 cup chopped
1 apple...........medium size [1 1/2 x size of an egg]
1 ml cardamon ...1/4 teaspoon
1 ml cinnamon ...1/4 teaspoon
240 g plain flour ... 2 cups
90 g light brown muscovado sugar ... 1/2 cup
90 g regular suger ... 1/2 cup
2 tsp baking powder
It has an oat crumble topping:
If the original recipe
6 eggs [360g]
1 tb baking powder
1 cup of milk [240ml]
works for you:
then the reduced recipe - on your numbers - would be
2 eggs [120g] plus 1 egg white [30g]
or just use 3 eggs [180g]
1 1/3 ts baking powder.
The meringue could be over-beaten.
The sugar syrup could have too much sugar in it
The syrup may be over-cooked.
It may have recrystallized. Does it contain an invert sugar or cream of tartar?
What is your recipe ?
Too much baking powder will raise you cake, but due to the weaker structure, it may collapse before it is baked, or just after.
Working in the dark ...
Depending on your baking powder [check the packaging], the "usual" US ratio is 1 1/2 teaspoons baking powder to raise 1 US cup [125g] flour..... 171 g flour would require an extra 1/3 teaspoon ....
As previously stated, this does not take into consideration any eggs or liquids.
Country Crock spreadable butter is 80% fat but it contains vegetable oil to keep it "spreadable". It does not appear to be a margarine product.
When creaming, the sugar crystals cut air-pockets in the solid fat. During baking the air pockets, expand causing the cake to rise. Substituting part of your solid fat with an oil product, means that there is less aeration - less rising . and resulting in the "greasy" feel ..