Pour 1 1/2 cups water into a 6- or 8-quart cooker. Set a heat- and pressure-safe trivet in the pot. Whisk the remaining 3 tablespoons warm water and the baking soda in a 2-quart, high-sided, round soufflé dish. Whisk in the condensed milk until smooth. Set this bowl on the trivet and lock the lid onto the cooker.
Optional 1Max Pressure Cooker Press Pressure cook on Max pressure for 30 minutes with the Keep Warm setting off.
Optional 2All Pressure Cookers Press Pressure cook (Manual) on High pressure for 40 minutes with the Keep Warm setting off.
When the machine has finished cooking, turn it off and let its pressure return to normal naturally, about 15 minutes. Unlatch the lid and open the cooker. Whisk the dulce de leche until smooth or use an immersion blender right in the insert to make the sauce super smooth. Pour the sauce into a small bowl and set it in the fridge for an hour or two. Cover and refrigerate for up to 5 days, microwaving small portions to loosen them up before serving.
Notes
Beyond • Unfortunately, dulce de leche cannot be made in a soufflé dish smaller than the one required here — and therefore cannot be made in a 3-quart cooker. Even halved, the mixture roils too much to be contained in a 1-quart baking dish. The recipe also cannot be doubled in the standard 2-quart baking dish we call for. • Serve dulce de leche over vanilla, butter pecan, chocolate, or any nut ice cream. It’s particularly delicious over cashew milk ice cream. • Drizzle warm dulce de leche over blackberries — and top with whipped cream. • Or spread it on toast as a change from Nutella. • Or dip salty pretzel logs into the sauce as a great dessert.