Preheat the oven to 350°F. Line a 9-inch cake pan with a sheet of parchment paper, pressing it into the pan and leaving overhang on all sides for easy removal and to help prevent overbrowning.
Brown the butter in a medium saucepan. When you see the first dark flecks around the edge of the pan, begin to whisk and keep going until it’s nutty. Pour it into a large bowl and go slice your almonds for the topping while the butter cools just enough that it won’t cook the eggs.
Thinly slice the almonds lengthwise. For the best flavor, slice them yourself if possible. Pre-sliced almonds will work, but the almond flavor may be milder.
Whisk the rest of the ingredients into the slightly cooled butter and scrape the batter into the tin
Top with the sliced almonds and bake for 45 to 50 minutes, until the center is soft and slightly squidgy but set. At the 30-minute mark, loosely lay a sheet of foil over the top to prevent the almonds from burning. Serve with vanilla ice cream, if desired.
