In a bowl, with a mixer on medium speed, beat butter and 1 cup sugar until well blended. Beat in the 2 whole eggs and the almond extract until completely incorporated, scraping down the sides of the bowl as necessary.
In a small bowl, stir together flour, cardamom, and baking powder; stir or beat into butter mixture along with half-and-half (dough will be stiff). Divide dough equally between two buttered and floured 9- by 5-inch loaf pans and spread or pat level.
Beat the egg white until foamy and brush over tops of dough. Sprinkle evenly with the almonds and remaining 2 tablespoons sugar.
Bake in a 350° oven until tops are golden, 25 to 30 minutes. Let cool on a rack for 5 minutes, then invert pans to release loaves onto rack. Let stand until cool enough to handle, about 20 minutes.
With a serrated knife, cut loaves crosswise into 3/4-inch-thick slices and arrange on a 10- by 15-inch baking sheet. Return to a 325° oven and bake until golden brown and firm to the touch, about 25 minutes longer. Let cool completely. Store airtight for up to 2 weeks.