Preheat oven to 350°F (175°C). Line a baking sheet.
Cream butter and sugar until smooth. Beat in egg yolk, vanilla, and almond extract.
Stir in flour and salt until dough forms. Chill 15 minutes if too soft.
Roll dough into 1-inch balls. Place on sheet 2 inches apart.
Press thumb into each ball to make a well. Spoon 1/2 tsp cherry jam into wells.
Sprinkle chopped almonds around edges if using. Bake 12–14 minutes until edges set.
Cool 5 minutes on pan, then transfer to rack. Dust with powdered sugar if you like.