I found this recipe on YouTube.
Flour 45 g
Cinnamon 1/2 tsp
Mix them well. Cut into butter around 50g. And make them into crumbs.
60g butter stir till smooth.
Add in 100g white sugar and stir till fluffy.
Beat in 1 large egg & 1/2 tsp vanilla.
Mix them well.
130g flour, 1 tsp baking powder, 1 tsp salt. Mix them well.
1. First add 1/3 flour part into butter mixture. Then add 1/2 milk. Mix them well.
2. Add another 1/3 flour & rest milk. Mix well.
3. Add the rest flour. Mix well.
4. Put batter into the pan evenly.
5. Spread blueberries (video says 2 cups blueberries, but I didn’t have that much) on the batter.
6. Sprinkle crumbs evenly on the top.
7. Preheat oven to 180 degree C and bake for 40-50 mins. ( I baked 40 mins. You can test with a toothpick).