Makes 36 Cookies
1 For the topping Adjust oven racks to upper-middle and lower-middle positions and heat oven to 350 degrees. Line 2 baking sheets with parchment paper. Combine almonds, sugar, and water in bowl. Spread almond mixture in single layer on 1 prepared sheet. Bake on upper rack until lightly browned, 10 to 12 minutes. Let topping cool completely on sheet. Break into small pieces; transfer to bowl. (Leave parchment on sheet).
2 For the cookies Increase oven temperature to 375 degrees. Whisk flour, baking powder, and salt together in bowl. Using stand mixer fitted with paddle, beat butter, sugar, and cream cheese on medium-high speed until pale and fluffy, about 3 minutes. Add egg, sour cream, and vanilla and beat until combined. Reduce speed to low and add flour mixture in 3 additions until just combined, scraping down bowl as needed. Cover bowl with plastic wrap and refrigerate until dough is slightly firm, about 20 minutes.
3 Working with 2 tablespoons dough at a time, roll into balls and space them 1 inch apart on prepared sheets. Bake cookies until dry on top but not browned, 10 to 12 minutes, switching and rotating sheets halfway through baking. Let cookies cool on sheets for 5 minutes, then transfer to wire rack. Let cookies cool completely.
4 For the frosting and filling Using stand mixer fitted with paddle, beat butter on medium-high speed until fluffy, about 30 seconds. Reduce speed to low and add sugar in 2 additions until combined. Increase speed to medium-high and beat until pale and fluffy, about 2 minutes, scraping down bowl as needed. Reduce speed to medium-low, add cream and almond extract, and mix until combined. Using serrated knife, cut off tops of cookies and reserve. Spread ½ teaspoon jam over 1 cookie bottom and replace top. Spread 1 heaping teaspoon frosting on cookie top and sprinkle with almond topping. Repeat with remaining cookies. Serve.