Heat oven to 350°F. Grease a 9-inch springform pan (or deep 9-inch cake pan) and line the bottom with parchment. Lightly oil the parchment.
Brew the tea: steep Harvest Carrot Cake Tea in 1 cup boiling water for 10 minutes (covered). Strain and cool. You’ll use 1/2 cup (120 g) in the batter; reserve the rest for brushing the cake if you want extra aroma.
Make fresh-milled almond flour from sliced almonds: Place 3 cups sliced blanched almonds in a blender or food processor with 1 tablespoon of the measured potato starch. Pulse (don't blend!) in short bursts, stopping to scrape down, until very fine and fluffy.
Measure out 2 1/2 cups (about 240 g) of the milled almond flour for the recipe.
Pre-dry the carrots (key for non-gummy crumb): spread grated carrots on a clean towel, squeeze hard to remove excess moisture, then fluff them back up.
In a large mixing bowl, whisk egg yolks with honey (or maple syrup), oil, orange zest, orange juice, vanilla, and salt until glossy and slightly thickened. Whisk in 1/2 cup (120 g) of the cooled brewed tea.
In a second bowl, combine 2 1/2 cups (about 240 g) fresh-milled almond flour with remaining potato starch, cinnamon, and ginger. Mix dry ingredients into the yolk mixture until just combined.
Fold in grated carrots and raisins (or cranberries)
In a clean mixing bowl, whip egg whites to stiff peaks. Fold 1/3 of the whites into the batter to loosen, then gently fold in the rest, keeping as much air as possible (this is the cake’s lift—no chemical leavening). The double-whisk Bosch mixer is great for this!
Pour into prepared pan and smooth the top. Bake 40–55 minutes, until deep golden, the center springs back, and a toothpick comes out with a few moist crumbs (not wet batter), about 200 degrees.
Cool in pan 15 minutes, then run a knife around the edge and release the springform. Cool completely on a rack.
Optional ‘tea perfume’: brush the top with 1–2 tablespoons reserved tea as the cake cools (light touch—think aroma, not soak).
Dust with powdered sugar right before serving. Serve at room temp. Store covered in the fridge up to 4 days; bring slices to room temp for best texture.