Heat the oven to 350°F. Line an 8 1/2 x 4 1/2-inch loaf pan with parchment paper.
Whisk the almond flour, whey protein isolate, baking powder, and sea salt. In a second bowl, whisk the eggs, Greek yogurt, melted butter, and 2 tablespoons everything seasoning until smooth.
Stir the wet mixture into the dry mixture just until a thick batter forms. Spread half of the batter into the prepared loaf pan.
Beat the cream cheese and egg yolk until smooth. Spoon the cream cheese mixture down the center of the batter, then cover with the remaining bread batter.
Sprinkle the final 1 tablespoon everything seasoning over the top. Bake for 42 to 48 minutes, until the loaf is golden and the center feels set when lightly pressed.
Cool the bread in the pan for 20 minutes, then transfer it to a rack. Let it cool completely before portioning so the creamy ribbon stays distinct and the crumb remains tender.