Pineapple doesn't have much of a change to appear on the menu otherwise in traditional Japanese sweets, so this is quite nice. It's usually made in a square shape, but you also fine pineapple-shaped molds.
I love the filling, and use it for more traditional Japanese sweets as a very surprising 中餡 (like the かるかん饅頭).
Pineapple has a rich symbolism of hospitality in Europe, so it's not completely out of place.
Recipe
Jam: Cook down pineapple, then add sugar, then lemon, then butter. In the end, it shouldn't stick to your hands.
330 gr pineapple (with core, but without skin and little knobs), blended
110 gr sugar
40 gr butter
5 gr lemon juice
Shortbread: Add in the order below. The milk powder is important for the typical caseous taste (but maybe leave it away for a 茶事). Knead roughly, then rest for 30' at least in fridge.
50 gr butter, 20 gr powdered sugar (cream together)
35 gr egg
12.5 gr milk powder (sift!), 115 gr flour, ½ tsp. baking powder
Use about 20 gr filling and 30 gr dough and form filled balls as with normal 和菓子. If you go below that, they'll be very petite and the filling will be too little as to be satisfying.
Smash into their form
Bake at 170° for 8', turn, bake for another 5'. They should be barely golden.