- In a small bowl, dissolve the baking soda and salt in the boiling water. Set aside.
- In another bowl, cream the shortening, butter, sugar, and vanilla with an electric mixer. Add the egg and beat until smooth. Add the baking soda mixture and molasses and stir to combine. At low speed, add the flour. Divide the dough in half.
- With the rack in the middle position, preheat the oven to 180 °C (350 °F). Line two or three baking sheets with parchment paper or silicone baking mats.
- On a generously floured work surface, knead one piece of dough at a time for 1 minute and roll out to about ½-cm (¼-inch) thick. With an 8-cm (3-inch) round cookie cutter, fluted or not, cut out circles of dough. With a 3-cm (1 ¼-inch) round cookie cutter, fluted or not, cut out the centre of half the circles of dough. Keep the smaller round centres, proceeding in the same way, using the smaller end of a plain tip to cut out the centre hole. Place the cookies of the same size on the same baking sheet. Reuse other scraps to make more cookies.
- Bake, one sheet at a time, for 6 to 7 minutes for large cookies and 4 minutes for small. Let cool on the baking sheet.
- In a bowl, stir the apple jelly with a whisk until smooth. Garnish the bottom of each large cookie with no holes with about 10 ml (2 teaspoons) of apple jelly and close with the cookies with the hole. For small cookies, use 2.5 ml (½ teaspoon) of apple jelly. Freeze the cookies in an airtight container, separating each layer with a sheet of parchment paper.
Freshly made cookies are slightly crispy, but freezing makes them soft and tender.