1. Make the almond simple syrup - In a small sauce pan, combine 1/2 cup granulated sugar and 1/2 cup water. Bring to a boil. Remove from heat, cool completely. Add in almond extract. Refrigerate until ready to use. This can be made up to 3 days ahead.
2. Make the apple cream - In the bowl of a stand mixer or a large bowl with handheld mixer, add the butter and the remaining 1/2 cup granulated sugar. Beat until light and creamy, about 3 minutes. Add the eggs one at a time, mixing well. Stir in almond meal, powdered sugar, salt, and Apple Pie Spice. Mix well. Refrigerate until ready to use. This can be made up to 3 days ahead.
3. To assemble - Preheat oven to 375ºF.
4. Lay the brioche slices on cookie sheet lined with parchment paper or a silicone mat.
5. Brush each piece of brioche with almond syrup. Then spread 2-3 tablespoons apple cream, followed by a single layer of apple slices. Then cover with almonds.
6. Bake for 10-12 minutes or until almonds are golden brown. Serve warm.
Stale bread works best - I like to cut the bread and let it sit overnight uncovered.