Low Carb Miso Toffee Brown Butter Chocolate Chunk Cookies

The finished cookies — golden, caramelised toffee pools, flaky sea salt

Why This Recipe Works

I have been low carb for five years. In that time I have tested more cookie variations than I can count — different flour blends, sugar substitutes, leavening combinations, chilling times. These cookies are the result of all of that testing.

What makes them special is the combination of three deeply flavoured elements working together: properly browned butter taken almost to the point of burning, white miso paste folded into a homemade toffee slab, and blended isomalt and coconut brown sugar in place of refined sugar. The result is a cookie with extraordinary depth — caramel, nutty, salty-sweet — that happens to be low carb.

At roughly ~227 calories and ~20g net carbs per 45g cookie these are far lighter than any bakery equivalent without sacrificing a single thing on flavour or texture.

Ingredients

Here is everything you need, with the net carb contribution of each ingredient so you can see exactly where the carbs are coming from.

Miso Toffee Slab

• 57g Kerrygold butter0g
• 30g coconut brown sugar7g
• 70g isomalt — blended to fine powder~3g net
• 35g white miso paste~4g
• 30g My Protein toffee drops~4g
• 4g vanilla bean extract0g

Cookie Dough

• 190g Kerrygold butter — browned0g
• 80g coconut brown sugar80g → ~20g per cookie batch total
• 110g isomalt — blended to fine powder~5g net whole batch
• 1 whole egg + 1 egg yolk, room temperature~1g
• 12g vanilla bean extract0g
• 2g fine sea salt0g
• 105g wholemeal flour~65g
• 80g hazelnut flour~12g
• 40g oat fibre0g net
• 2g baking soda0g
• 2g baking powder0g
• 130g Diablo chocolate chips~20g net
• 2g flaky sea salt — for topping0g

How I Made This Low Carb

The original inspiration for these cookies uses all-purpose flour and regular sugar. Here is how each element was swapped without losing anything on flavour or texture.

• Flour blend instead of AP flour — wholemeal flour, hazelnut flour and oat fibre together replicate the structure of plain flour. Hazelnut flour adds fat and richness. Oat fibre adds structure with zero digestible carbs.
• Isomalt + coconut brown sugar instead of white sugar — isomalt provides sweetness without spiking blood sugar and prevents the crystallisation you get from pure coconut sugar. A small amount of coconut brown sugar is kept for depth of flavour — isomalt alone tastes flat.
• Diablo chocolate chips — sugar-free chocolate that melts beautifully and gives proper chocolate pools rather than the grainy texture of some sugar-free alternatives.
• Miso paste in the toffee — adds umami depth and a salty caramel note that makes the cookie taste far more complex than it has any right to at this carb count.

Instructions

This section walks through the method step by step. See the full recipe card at the bottom for a condensed printable version.

The miso toffee slab — deep amber caramel with miso stirred through

Step 1

Make the miso toffee slab

Melt 57g butter in a saucepan over medium heat. Add 30g coconut brown sugar and 70g blended isomalt. Stir continuously until deep amber — 4 to 5 minutes. Remove from heat. Stir in 35g miso paste and 4g vanilla until smooth. Stir in 30g toffee drops. Pour onto a parchment-lined tray as thin as possible. Freeze minimum 30 minutes until rock solid.

Frozen toffee slab chopped into 1cm pieces ready to coat in oat fibre

Step 2

Chop and coat the toffee

Once rock solid, chop into irregular 1cm chunks. Toss all pieces in 5g of your measured oat fibre — this dry coating slows the melt in the oven, giving the cookie walls time to set before the toffee liquefies. Return to the freezer immediately.

Butter going deep amber — take it almost to the point of burning

Step 3

Brown the butter

Melt 190g butter in a light-coloured saucepan over medium heat. Stir occasionally as it foams. Once the foam quiets and the butter turns deep amber — almost burnt — remove from heat immediately. Scrape every brown bit into a bowl. Cool 10 to 15 minutes until room temperature.

Coconut brown sugar, isomalt and egg yolks whisked into the cooled brown butter

Step 4

Build the dough base

Whisk 80g coconut brown sugar and 110g blended isomalt into the cooled brown butter until smooth. Add 1 whole egg, 1 egg yolk, 12g vanilla and 2g salt. Whisk for a full 2 minutes until the mixture looks thick, pale and glossy.

Always sieve the flour blend — removes lumps and aerates without extra mixing

Step 5

Sieve in dry ingredients — do not overmix

Whisk together 105g wholemeal flour, 80g hazelnut flour, 35g oat fibre (the remaining after the 5g used for coating), 2g baking soda and 2g baking powder. Sieve into the wet ingredients. Fold gently until 75% combined — a few streaks of flour still showing is correct. Stop here. Do not overmix.

Chocolate and toffee pieces folded in — every piece buried inside the dough

Step 6

Fold in chocolate and toffee

Fold in 130g Diablo chocolate chips first. Then add the frozen oat-fibre-coated toffee pieces straight from the freezer. Fold with as few strokes as possible — every piece must be fully buried inside the dough. Reserve a small handful of each for pressing on the tops only.

45g balls rolled tight — ready for the 24 hour freeze

Step 7

Shape, seal and freeze for 24 hours

Portion into 45g balls — weigh every one for consistency. Roll firmly between palms into tight smooth spheres — no surface cracks, as cracks are escape routes for melting toffee. Press reserved toffee and chocolate on the very top surface only, never the sides or base. Cover and freeze for 24 hours minimum — the flavour deepens significantly overnight.

Tips for Perfect Cookies

Fresh from the oven — chocolate squares, toffee pools, flaky salt

Variations

• Swap Diablo milk chocolate for Diablo dark for a more intense, less sweet chocolate flavour
• Add 25g full fat milk powder toasted in butter before browning — deepens the butterscotch note dramatically
• Replace toffee drops with chopped sugar-free caramel pieces for a different texture inside the cookie
• Add 1g xanthan gum to the dry ingredients if you want extra chew without tapioca starch
• Use hazelnut paste instead of vanilla extract for a Ferrero Rocher-style flavour profile

Frequently Asked Questions

The toffee pool and melted Diablo chocolate

Storage