How to make
In a bowl, beat the eggs with the sugar, vanilla, lemon zest, soft butter and rum. To them, gradually add the sifted flour while stirring constantly. Knead a smooth and soft dough.
From the dough, form small balls the size of a walnut and arrange them in a tray covered with baking paper. You're going to need a wooden spoon to form the indentation for the jam.
Wet the end of the handle with water and poke an indentation in the middle of each (not all the way down though).
Put the tray in a preheated 360°F (180 °C) oven and bake about 10 min. (without baking to a crisp).
Leave them to cool and fill the indentation with 1/2 tsp of well stirred strawberry jam, sprinkle with a little powdered sugar. These strawberry butter treats are fantastic. Store in a box.