One-Bowl Rhubarb & Rye Muffin Slab

Instructions

1. 1

   Preheat your oven to 400°F (200°C). Line a 9x13-inch quarter sheet pan with parchment paper, leaving an overhang on the long sides so you can lift the slab out later. Don't skip the parchment; rhubarb likes to stick.

   5 min

   Tip: A metal pan gives you much better edge crisping than glass or ceramic.

2. 2

   In a large mixing bowl, aggressively whisk the 1/2 cup (113g) cultured unsalted butter, 3/4 cup (150g) granulated sugar, 2 large eggs, 1 cup (240g) whole milk yogurt, and 1 tsp vanilla bean paste. You want a perfectly smooth, homogenous emulsion before the flour hits the bowl. Let time do the work here—whisk for a solid 60 seconds.

   3 min

   Tip: If your yogurt was cold, your melted butter might seize into tiny clumps. Don't panic, just keep whisking. It will bake out fine.

3. 3

   Dump the 1 cup (130g) all-purpose flour, 3/4 cup (85g) dark rye flour, 1 1/2 tsp baking powder, 1/2 tsp baking soda, and 1 tsp kosher salt directly onto the wet ingredients. Fold with a flexible spatula just until the dry streaks disappear. Overmixing here makes the crumb tight like a bad alibi. Stop when it still looks a little shaggy.

   2 min

   Tip: Rye flour loves hydration, so a slightly lumpy batter is exactly what we want.

4. 4

   Gently fold exactly half, or 1 cup (125g) fresh rhubarb, into the batter. Scrape the entire mixture into your prepared sheet pan and nudge it into the corners using an offset spatula or the back of a spoon.

   2 min

5. 5

   Scatter the remaining 1 cup (125g) fresh rhubarb evenly over the top, pressing the pieces very lightly into the batter so they anchor. Aggressively shower the entire surface with the 3 tbsp turbinado sugar.

   2 min

   Tip: The turbinado sugar is non-negotiable. It creates the shatter-crisp crust that separates café-level baking from a sad grocery store muffin.

6. 6

   Bake on the middle rack for 20-22 minutes. You are looking for visual cues: deeply bronzed edges, a cracked sugary top, and a center that springs back when firmly tapped. A toothpick inserted in the center should come out clean (minus any jammy rhubarb).

   22 min

   Tip: Watch the color. The dark rye flour means the batter starts out tan, so look for a dark golden-brown finish.

7. 7

   Use the parchment overhang to lift the slab onto a wire rack. Let it cool for at least 15 minutes before slicing into squares. Slicing too early lets the steam escape, ruining your lacy crumb.

   15 min

   Tip: Cut into 12 squares. Eat the edge pieces first; they have the best caramelization.