Combine the butter and olive oil.
Mix the egg and sugar and mix for a few minutes until airy.
Stir in the milk, then add the butter and olive oil, followed by the lemon juice and lemon zest.
Fold in the flour, baking powder and salt.
Spread the batter in a thin sheet in a baking pan lined with parchment paper and bake in the preheated oven at 350F for 10-15 minutes or until slightly golden brown.
When done, allow to cool down in the pan then cut small discs, big enough to fit your miniature silicone moulds.
Place aside wrapped in plastic wrap.