Take mango pulp in a bowl. Add lemon juice and lemon zest to it.
Add corn flour, sugar and mix once.
Add butter and start cooking at low flame.Keep stirring gently .
Once the butter melts, add egg yolks, sprig vanilla extract and cook for 2-3 minutes at low flame.
Stop cooking when it gets quite thick .It will coat the back of the spatula. A spread consistency.
Cool it and transfer to a sterilised jar . You can store for a week in refrigerator .