Rye & Caramelized Onion Babka

Makes 1 loaf (8.5 x 4.5″)

Inspired by the flavors of a classic Jewish deli, this savory babka is made with rye dough and filled with deeply caramelized onions and whole grain mustard.

It uses the same milk bread dough as my Chocolate Babka, but this time with a bit of rye flour subbed in and toasted caraway seeds. You get that same pillowy texture, but with a punchier, savory edge. The filling is simple but deeply flavorful. For caramelizing the onions, I have you add a pinch of sugar and briefly steam them with water — two easy tricks that speed up the process. The onions are then tossed with whole grain mustard, bringing some heat and tang that pairs perfectly with the rye and caraway.

Instead of the traditional babka shaping where you slice the log down the middle to expose the swirl, this version uses an alternative twist. The log is kept intact and twisted together, giving the loaf a smooth top and a more structured rise.

It’s delicious on its own, but toasted and piled high with pastrami or turned into a Reuben…it’s next-level.

Note: If your stand mixer is larger than a standard 4.5–5 quart, I recommend doubling the recipe. A single batch may be too small to knead effectively in a large bowl.

WHAT YOU’LL NEED

INGREDIENTS

Tangzhong

  • ¼ cup whole milk (60g)

  • 1 ½ tbsp all-purpose flour (13g)

Rye Babka Dough

  • 1 ¾ cups all-purpose flour (210g)

  • ¼ cup dark rye flour (30g)

  • 2 ½ tbsp granulated sugar (35g)

  • 1 ¼ tsp instant yeast (5g)

  • 1 ¾ tsp Diamond Crystal kosher salt (6g) (or 1¼ tsp Morton kosher salt)

  • 1 tsp toasted caraway seeds

  • ¼ cup lukewarm whole milk (under 110°F) (60g)

  • 1 large egg + 1 egg yolk, room temperature

  • All cooled tangzhong

  • 6 tbsp very soft unsalted butter (85g)

Caramelized Onion Filling

  • 3 tbsp unsalted butter (42g)

  • 2 large yellow onions, thinly sliced

  • 1½ tsp Diamond Crystal kosher salt (9g) (or 1 tsp Morton kosher salt)

  • Small pinch sugar

  • ½ cup water

  • 2 tbsp whole grain mustard

Topping

  • Egg wash: 1 egg whisked with a splash of water

  • Extra caraway seeds

  • Sesame seeds (optional)

DIRECTIONS

Make the Tangzhong

  1. Whisk together milk and flour in a small saucepan until smooth.

  2. Cook over medium heat, whisking constantly, until a thick paste forms (like mashed potatoes), about 2–3 minutes.

  3. Scrape into a bowl and let cool completely before using (10–15 minutes).

Make the Dough & First Rise

  1. In a stand mixer with a dough hook, combine flour, sugar, yeast, and salt. Add the milk, egg + yolk, and all the cooled tangzhong. Mix on low for 2–3 minutes until no dry flour remains. You may need to pause and scrape the bowl or press in any dry flour by hand. The dough will feel firm and slightly dry at this stage — this is normal.

  2. Increase to medium speed and mix for 5–6 minutes until the dough is firm, elastic, and tacky.

  3. Add the butter 1–2 tablespoons at a time, mixing until each addition is fully incorporated before adding the next. Scrape bowl/hook as needed. Once all butter is added, mix 6–10 minutes on medium speed until the dough is smooth and glossy. It should stretch thin and translucent before tearing (a soft windowpane).

    Please note: If the dough hook struggles to incorporate the butter (common with smaller batches or rye dough), switch temporarily to the paddle attachment to fully emulsify the butter. Once incorporated, switch back to the dough hook for the final knead.

  4. Shape the dough into a ball and place in a lightly greased medium bowl. Cover with plastic wrap. Then, choose one of the following rise options:

    • Same-Day (Faster): Let dough rise at room temperature for 1½ to 2 hours, until slightly puffy. Turn dough out and press into a flat rectangle. Wrap tightly in plastic wrap and freeze for about 30 minutes, until firm and well chilled (not frozen solid).

      Note: Do not freeze much longer than 30 minutes — if you’re not ready to roll yet, transfer the dough to the refrigerator instead to prevent it from freezing through.

    • Overnight (Preferred): Let dough rest (covered) at room temperature for 1 hour to kickstart fermentation. Then turn out the dough, press into a flat rectangle, wrap tightly in plastic wrap, and refrigerate overnight (8–24 hours).

      Tip: Shaping into a clean rectangle here makes rolling later much easier.

Make the Onion Filling

  1. Melt butter in a large skillet or Dutch oven over medium heat.

  2. Stir in the onions, salt, and a pinch of sugar. Top with ½ cup water and cover for about 10 minutes.

  3. Remove the lid and continue cooking 20–30 minutes, stirring frequently and adding small splashes of water as needed to deglaze. Cook until deeply golden brown and jammy, with no visible liquid remaining.

  4. Measure out ¾ cup of the onions, mix with the mustard, and set aside to cool to room temp. Save any remaining onions for other use.

Shape & Second Rise

  1. Line and grease an 8.5 x 4.5″ loaf pan with parchment paper, leaving a bit of overhang on the long sides for easy removal after baking.

  2. On a lightly floured surface, roll the chilled dough to about 10 x 20 inches (long side facing you).

  3. Spread the cooled onions evenly in a thin layer, leaving a small border on each side.

  4. Roll up tightly from the long, 20-inch side, gently pulling the dough toward you as you roll to eliminate air pockets. Flip the log seam-side up and firmly pinch the seam closed along the entire length to fully seal.

  5. Gently roll the log back and forth to even the thickness and slightly lengthen. Trim the ends for a clean finish.

  6. Cut the log in half, dividing into two equal pieces.

  7. Place the two logs side by side and twist them together 3–4 times, pinching the ends to seal and twisting in opposite directions to tighten.

  8. Place into the prepared loaf pan and gently press down to settle the loaf evenly into the pan.

  9. Cover and let rise in a warm spot for 1.5–2 hours, until puffy.

    Tip: Take a before/after photo to help gauge rise.

  10. Once risen, brush with egg wash on all exposed surfaces and top with a sprinkle of sesame and caraway seeds.

Bake

  1. Preheat oven to 350°F (175°C).

  2. Bake for 50–55 minutes, placing the pan on a baking sheet. Tent with foil after 25–30 minutes to prevent over-browning. Internal temp should read 195–200°F (90–93°C).

  3. Let cool for at least 1 hour before slicing to allow the crumb to fully set.

  4. Wrap tightly once cooled and keep 2–3 days at room temp, or freeze for longer storage.

RECIPE NOTES & TIPS

  • The rise time can vary based on the temperature of the dough and the room. If you have a cool kitchen, the rise may take longer than the times in the recipe. Go by how the dough looks, it should be puffy and airy, rather than just the clock.

  • If you prefer traditional babka shaping with the exposed swirl, you absolutely can. Follow the shaping process outlined in the Chocolate Babka recipe instead, slicing the log lengthwise and twisting with the cut sides facing up.

  • Because this filling is onion-based (rather than a thick sugar paste like chocolate or cinnamon), you may notice slightly more gaps in the swirl. That’s normal. Fully caramelizing the onions to reduce excess moisture, rolling the dough tightly, sealing the seam well, and avoiding overproofing will help minimize larger air pockets.

  • The babka will firm up slightly overnight as it cools. Wrap it tightly once fully cool and reheat slices gently to restore softness.

  • To be precise and consistent when baking, I recommend using a Digital Food Scale. The one I linked is relatively inexpensive and in my opinion, a great investment for any home kitchen! But if you don’t have one, I’ll always include cup measurements as well.