Prep the pan. Heat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment, leaving a slight overhang for easy lifting. Lightly grease the parchment.

Whisk the wet ingredients. In a medium bowl, whisk the melted butter and sweetener until glossy and combined. Whisk in the eggs, vanilla, and almond extract until the mixture looks smooth and slightly thick.

Add cocoa and salt. Sift in the cocoa powder to avoid lumps. Add salt and whisk just until no dry streaks remain. The mixture will look shiny and dark.

Stir in dry ingredients. Sprinkle in baking powder. Fold in the almond flour with a spatula until evenly combined. The batter will be thick but spreadable.

Boost the fudginess. Fold in the almond butter or oil until the batter loosens slightly and becomes silky.

Add chocolate (and nuts if using). Stir in sugar-free chocolate chips and optional nuts. Reserve a few to sprinkle on top.

Spread and smooth. Scrape the batter into the prepared pan. Smooth the top with a spatula and sprinkle over the reserved chips or nuts.

Bake. Bake for 18–24 minutes, depending on your oven and preferred fudginess. Pull them when the edges are set and the center is just slightly soft. A toothpick should come out with moist crumbs, not wet batter.

Cool completely. Let brownies cool in the pan on a rack for at least 30–45 minutes. For the cleanest slices, chill for 20 minutes after cooling, then lift out and cut.

Serve. Slice into 9 large or 16 smaller squares. Enjoy as-is or with a small dollop of sugar-free whipped cream.