Preheat oven to 350° and line 2 baking sheets with parchment. In a food processor, pulse almonds until finely chopped but not so fine they turn into flour. Transfer to a medium bowl and whisk in flour and salt.
In a medium saucepan over medium heat, melt butter, brown sugar, cream, and granulated sugar, stirring constantly. Bring to a boil and cook 1 minute. Remove from heat and stir in vanilla. Whisk in dry ingredients, then let cool 5 minutes.
Using a teaspoon measuring spoon, spoon batter onto prepared baking sheets, spacing 3" apart.
Bake until golden and batter has spread into a lacey pattern, 6 to 8 minutes. Let cool on baking sheets 5 minutes. Peel cookies from parchment, transfer to a wire rack, and let cool completely (they will continue to crisp as they cool).
If desired, spread backs of cookies with chocolate or drizzle over tops. Refrigerate to harden chocolate, about 20 minutes.
Make Ahead: Cookies can be made 3 days ahead. Store in an airtight container at room temperature.