This Mason Jar Boston Cream Pie Parfait has become my go-to dessert whenever I want the nostalgic flavors of Boston Cream pie with far less fuss. I first assembled these for a backyard brunch when I needed something portable that held up in warm weather. Instead of wrestling with a layered cake, I baked a light sponge, whisked a silky vanilla custard, and finished the jars with a shiny chocolate ganache. The result was the same comforting contrast of tender cake, creamy filling, and bittersweet chocolate—but easier to serve and impossible to resist.

I discovered how well the elements behaved in jars while testing make-ahead desserts for a picnic. The airtight mason jars kept each component fresh, and guests loved the visual of alternating layers. Texturally, the sponge soaks up a little custard and becomes pillowy; the custard itself is rich yet bright with vanilla; and the chocolate forms a gleaming top that cracks pleasantly with the spoon. Every bite echoing the classic dessert felt like a mini celebration, and my family now requests these for birthdays and casual get-togethers alike.

Ingredients

• Vanilla custard filling: 1/4 cup granulated sugar, 1 cup whole milk, 2 tablespoons cornstarch, 1 tablespoon unsalted butter, 3 large egg yolks, 1 teaspoon vanilla extract, 1/4 cup heavy cream. Use whole milk for richness and stability; store-brand whole milk works fine, and pasteurized eggs are fine for cooking.
• Sponge cake: 1 1/2 cups sifted cake flour, 1 1/4 teaspoons baking powder, 1/4 teaspoon salt, 1/2 cup whole milk, 4 tablespoons unsalted butter (cut into tablespoons), 3 large eggs at room temperature, 3/4 cup granulated sugar, 1 teaspoon vanilla extract. Cake flour yields a tender crumb; if you only have all-purpose, remove 2 tablespoons per cup and replace with cornstarch for a similar texture.
• Chocolate ganache: 3 ounces semi-sweet or bittersweet chocolate finely chopped, 1/2 cup heavy cream, 1/2 teaspoon vanilla extract. Use a good-quality chocolate bar for the best sheen and flavor—Valrhona or Ghirardelli are reliable choices.

Instructions

Make the vanilla custard: In a medium bowl, whisk together 3 large egg yolks, 1/4 cup granulated sugar, and 2 tablespoons cornstarch until smooth and pale. Bring 1 cup whole milk to a gentle boil in a saucepan—watch closely so it does not boil over. Temper the yolks by whisking about 1/3 cup hot milk into the yolk mixture, then return it all to the saucepan. Over medium-high heat, whisk constantly until it comes to a boil; continue whisking for 60 seconds to activate the cornstarch and thicken. Remove from heat, whisk in 1 tablespoon unsalted butter until melted, then strain through a fine-mesh sieve into a bowl. Stir in 1 teaspoon vanilla extract, cover the surface with plastic wrap to prevent a skin, cool to room temperature, then chill for at least 2 hours. Bake the sponge cake: Preheat oven to 350 degrees F and grease a 9-inch cake pan. Whisk together 1 1/2 cups sifted cake flour, 1 1/4 teaspoons baking powder, and 1/4 teaspoon salt. In a small saucepan, combine 1/2 cup whole milk and 4 tablespoons unsalted butter and heat until the butter melts; set aside. In a mixer with a whisk attachment, beat 3 large room-temperature eggs on high for 1 minute, then gradually add 3/4 cup granulated sugar and 1 teaspoon vanilla and continue beating until pale and tripled, about 6 minutes. Fold in the flour in three additions, then reheat the milk mixture to just under a boil and fold it in all at once. Pour into the prepared pan and bake 20–25 minutes until the cake springs back. Cool 10 minutes, run a paring knife around the edge, invert onto a rack, and cool completely. Prepare the chocolate ganache: Bring 1/2 cup heavy cream to a boil in a small saucepan, remove from heat, and pour over 3 ounces finely chopped semi-sweet chocolate. Let sit 30 seconds, then stir until smooth. Stir in 1/2 teaspoon vanilla extract. Cover and let cool about 10 minutes to thicken slightly before assembling so it won’t be too runny in the jars. Whip the custard light: When custard is chilled, transfer it to the mixer bowl, add 1/4 cup heavy cream, and whip on high with the whisk attachment just until light and soft peaks form, about 1 minute. This step adds aeration for a spoonable texture that layers beautifully. Slice the sponge and assemble: Using a long serrated knife, slice the cooled cake horizontally or into 1-inch chunks. Place a handful of cake pieces into the bottom of each mason jar, top with a layer of whipped custard, then a drizzle of ganache. Repeat layers until jars are filled, finishing with ganache. Serve immediately or refrigerate with lids on for up to 48 hours.

Storage Tips

Store assembled jars covered with lids in the refrigerator for up to 48 hours. For best texture, assemble no more than one day ahead if you want the cake to retain a bit of bite; for maximum convenience, make the custard and cake separately and assemble within 24 hours. Use airtight containers if you remove jars from their lids to prevent absorption of fridge odors. To reheat slightly, remove lid and warm in a 300 degrees F oven for 5–7 minutes—note this will soften the ganache. Discard if left at room temperature more than two hours due to the dairy and egg content.

Ingredient Substitutions

If you need dairy-free options, replace whole milk and heavy cream with full-fat canned coconut milk and use vegan butter in the sponge; swap the custard with a cornstarch-thickened coconut pastry cream. For gluten-free, use a 1:1 gluten-free cake flour blend and add 1/8 teaspoon xanthan gum for structure. To reduce sugar slightly, decrease the sugar in the sponge by 2 tablespoons and in the custard by 1 tablespoon—this will reduce sweetness while preserving texture. For a boozy variation, brush the sponge with 1 tablespoon rum or coffee liqueur before layering.

Serving Suggestions

Serve chilled with a dusting of cocoa powder or a few fresh raspberries on top for brightness. For brunch, pair with a sharp coffee or espresso; for dessert, present alongside brittle or toasted nuts for contrast. These jars also make elegant gifts—tie a ribbon around the jar and include a small wooden spoon for a charming presentation.

Cultural Background

Boston Cream pie traces back to 19th-century American baking and is considered the official dessert of Massachusetts. Despite its name, it’s actually a cake—layered sponge filled with pastry cream and glazed with chocolate. This jar adaptation preserves those classic components while translating them into single-serve format, reflecting modern preferences for portability and make-ahead convenience.

Seasonal Adaptations

In summer, add fresh berries between layers and lighten the custard by folding in whipped cream. In fall, flavor the custard with a pinch of ground cinnamon or cardamom and finish the ganache with a splash of bourbon. For winter holidays, stir orange zest into the custard and use dark chocolate ganache for a festive, citrus-chocolate pairing.

Meal Prep Tips

Make the custard and cake up to two days in advance. Keep custard chilled and cake wrapped tightly at room temperature for one day or refrigerated for two. Store ganache at room temperature if cool or refrigerated if your kitchen is warm—gently rewarm to pourability. When assembling, use a piping bag for neater layers and a spoon for ganache. Use wide-mouthed 8-ounce mason jars for easy scooping and balanced proportions.

These mason jar parfaits combine practicality with nostalgia—once you try them, you’ll find many occasions where a portable Boston Cream-inspired treat is simply perfect. Make one batch and watch guests reach for a second jar.